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successful growingThe most important characteristic that a grower looks for in a hydroponic medium is uniformity. Not just uniformity in a set of blocks or units, but also uniformity within the individual block or unit of medium. Especially In an ebb and flood system, the capillarity (upward movement) of water in the medium is important as well, as it helps the slabs stay wet on the top as well as the bottom.

Why is uniformity so important?When growing plants in a controlled environment, plants grow from a smaller amount of media than when grown outdoors in soil. It is therefore crucial that root growth is maximized inside that small area of media. When a media lacks uniformity, nutrient solution cannot spread evenly throughout the area, and will result in restricted root growth.

Tests for Evaluating Growing Media

Why is capillarity so important? Good capillarity is vital when using an ebb and flood system. When flooding the tray a few inches, the nutrient solution should spread (wick up) evenly and quickly to the rest of the medium. Grodan GRO-BLOCKS™ have excellent capillarity. Fast capillary movement in a uniform product ensures good root growth in flood systems.

The graphics above show the results of a capillarity test using blue dye. Both blocks flooded for ten minutes in the same tray.

On right, see PET plastic grow medium. Below, examine the Grodan GRO-BLOCK.

SUCCESSFUL GROWING

SUCCESSFUL GROWING | 1

Even root distribution in various Grodan products. Top left to right: Root growth in GRO-SLABS™, Root Growth in GROW-CUBES™. Bottom: Typical root growth in Grodan GRO-BLOCK™.

TEST 1: BLUE DYE TEST

You need highly concentrated blue food coloring. For this reason, it is a good idea to wear gloves for this test. Choose the media you want to test, then use plain water to completely saturate all the media.

Using your normal irrigation system, give each test subject equal amounts of blue water, whether you are using drip or ebb and flood. Make sure that the blue dye is very concentrated before you test. It will be messy but will reveal a dramatic difference.

How to test the quality of hydroponic mediaHere are two simple tests you can do to determine the quality of your hydroponic media.

With drip irrigation, you will see an even hue across the whole unit of Grodan. With ebb and flood systems, you will see a better capillary movement and distribution of the blue dye throughout the Grodan GRO-BLOCK™.

Notice the uneven light color with other rockwool on the top versus dark hue of color evenly spread in the Grodan slab on the bottom.


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TEST 2: ROOTING TEST:

Sometimes the blue dye test isn’t enough to show a dramatic difference. A rooting test will take longer, but reveal clearer results on the spread of roots in Grodan versus another medium.

First, wet and pH adjust the growing media as normal. Then, place two plants on the Grodan slab and two plants on the comparison slab or grow bag.

Remove plastic wrapping from a Grodan MINI-BLOCK™. Insert the MINI-BLOCK™ inside the slab bag, centered between the two plants. Do the same with another MINI-BLOCK™ for the comparison medium.

Now allow some time for the plants to grow. Tug on the MINI-BLOCKS after a few days to see if they are anchoring into the media. How well and how soon they anchor into the media is a sign of good root growth.

After about two weeks, pull the MINI-BLOCKS™ off the slab or grow bag and examine root distribution. The MINI-BLOCK™ in the best media will be anchored so well that it will actually be difficult to remove from the slab or grow bag!

To test a loose potting media, such as clay pellets, peat, coco mix, or Grodan GROW-CUBES™, place it in a long grow tray instead of in a regular tall pot. This will allow for enough space between the two plants in order to insert the MINI-BLOCK™.

Wilt-Proof Your Plants

When growing a plant out of Grodan stonewool, all the water (plant food/nutrient) poured into it is instantly available to the plant.

If the water content of the Grodan media drops to zero—the plant will droop severely. This is natures warning that NOW is the last chance to water for the plant to survive. Of course it is always better to water before the media is bone dry. The best way to determine whether or not the plant requires watering is to feel the weight of the pot. If it feels light—then water.

When growing a plant out of peat/soil, an average of 35% of the water content is unavailable to the plant and a slow wilting process begins. Often it is such subtle change that it is often overlooked. Then, by the time it’s noticed, the wilting process is too advanced to save the plant.

This is why we say that a “Grodan” plant is more forgiving, as it will stay healthier longer, and recoup faster if the grower forgets to water, or the pump fails.

Tests for Evaluating Growing Media, cont.

Insert Grodan MINI-BLOCK here, between the two plants in the

GRO-SLAB or tray


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Using the Dutch Pot System

Assembling your own hydroponics system may take a little time, but it can also save you some money. The BATO® buckets (a.k.a. Dutch Pot system) uses top watering, which is the best way to water for most growing media.

The Dutch Pot System consists of the following:• Select Dutch buckets; black (to prevent algae

growth) or beige (to keep the contents cooler).

• Concrete blocks to support the buckets and the drain pipe.

• A stock tank (no taller than the concrete blocks). Optional: Make a lid out of a nylon mesh - possibly woven ground cover. This will help prevent debris from your system getting into your stock tank.

• 1/2” tubing (about 1 ft../bucket plus a little extra to reach into the tank).

• PVC drain pipe with 1 1/2” (inside diameter and 50 mm or 2“ outside diameter). Estimate 1 ft../ bucket. Either cut out a 1” wide piece from the whole length of the pipe or simply drill a 1“ hole for each bucket. The outlets from the BATO bucket must fit inside the canal to collect the drain water. Alternatively use two pieces of rain water gutter. The top piece can then be removed for easy cleaning of the gutter.

• A pump for the stock tank.

• For each bucket, figure 1-2 drip stakes and ¼” tubing (spaghetti tubing) from the stake to the ½” tubing.

• A 1” plastic or net pot around the ‘elbow’ in the bucket will minimize roots and debris from getting into the elbow.

• We recommend 2 stakes if using clay pellets alone. This insures that the irrigation will reach all corners of the bucket. If you use Grodan GROW-CUBES™ or Granulate (alone or with clay), only one stake per bucket is needed.

• Growing Media. Propagate plants in 1 1/2” Grodan A-OK plugs™, then pot up in a Grodan GRO-BLOCK™. Once the roots extend about 1” from below the block, remove the plastic from the block and transfer the plant block to the bucket. Fill the bucket with Grodan GROW-CUBES™.

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System setup


NOTE: For a wetter mix: Fill up the lower section of the bucket with clay pellets, then top up with absorbent Grodan granulate.

Drawing shows four buckets with 2 pieces of micro tubing per bucket. The basket stakes keep each of the micro tubings in place in the bucket.

Position the stock tank so that the water only pumps out to a maximum of 6-7 feet. If longer, there might not be enough pressure for the water to reach your last buckets – or they will receive considerably less water than those close to the pump.

Side View - Dutch Pot System

Top View - Dutch Pot System

A 150-175 gph pump will run to 6 buckets through 12 basket stakes.

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This product is specifically designed to house a large plant... (think Ficus tree) or to grow a mother plant. Big Mama’s volume is a staggering 512 oz. versus Hugo’s 216 oz. Rockwool “RULES” when it comes to wicking up to 4 inches in height. But beyond that, Rockwool will retain less and less moisture. Thank gravity for that. This is why Grodan has specific recommendations for using the Big Mama.

• First, place ONLY a well-rooted 3” or 4” GRO-BLOCK on top to ensure the optimum health of the plant.

• Second, Drip irrigation is the most effective system for the Big Mama, but any top watering will work. Placing one dripper stake into the top block, and a second one into the Big Mama is sufficient to maintain proper moisture levels. Using the Big Mama in an Ebb & Flood system is NOT recommended.

What to know about the BIG MAMA™

A) Both blocks were saturated using a garden hose. For conditioning and ir-rigation, two dripper stakes were inserted -one in each block.

B) Both blocks were saturated using a garden hose. For condi-tioning and irrigation, only one dripper stake was inserted into the top block.

C) Only the top block was saturated to start. Then, for condi-tioning and irrigation, just one dripper stake was inserted into the top block.

Lessons Learned1. It’s a terrible idea to wet up a dry Big Mama

using only one drip stake!

2. Before using, ALWAYS soak the Big Mama completely with a garden hose.

3. Conditioning and irrigation works best when using two drip stakes per block.

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Testing Big Mama to see what works best1. Use a garden hose to completely saturate the

blocks with water.

2. Insert two drippers into the block. Fill the tank with pH 5.5 water, and water each block long enough so that the block receives 2.5 gallons of water. This ensures a complete flush of the block. If you only have a few blocks, skip steps 1 and 2, and simply use the ½” hose from the pump and hand-water with pH 5.5 from top down, until completely saturated.

3. Discard the drain water. Mix up the same nutrient solution that you have been using for the plants you are about to transplant. Irrigate until each block has received 2.5 gallons of nutrient. Then adjust tank back to pH 5.5.

4. Place a 3” or 4” block with well-rooted plant onto Big Mama. Insert one drip stake into the right side of the plant in the small block and one drip stake into the Big Mama on the opposite side of the small block. It’s acceptable if the Big Mama’s surface doesn’t feel particularly moist. Less surface moisture on Grodan will lessen algae growth.

5. After placing smaller plant on top of Big Mama, minimize initial watering to encourage rooting into the Big Mama. Watch to make sure the small block doesn’t become too dry. To achieve this; place both drip stakes immediately below the small block. Angle the drip stakes in - under the block. For the first few days after transplant; irrigate six short 1 minute cycles per day. As the plant grows, add more irrigation cycles and increase to 2-3 minute per cycle.

Conditioning is complete when drippers have released 2.5 gal of pH 5.5 water per block.


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Understanding Basic Irrigation Systems

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There is a huge assortment of irrigation components available and it is not easy to know which way is the best way to go. For hydroponic vegetables, the choice is often ebb and flood or drip irrigation.

What’s the basic difference between them?DRIp IRRIGaTION (TOp waTERING)

With drip irrigation, fresh nutrient solution is dripped down through the top of the block.

This is the way Grodan intended for their products to be irrigated. When top watering, Grodan products are designed to allow the water to spread quickly throughout the product and force out the old nutrient solution from the stonewool. Therefore if growing in stacked units, like Grodan GRO-BLOCKS on top of GRO-SLABS, always choose a top watering system.

EBB aND fLOOD

With Ebb & Flow (Flood), fresh nutrient solution is pumped up from below. With Ebb & Flow (Flood), fresh nutrient solution is pumped up from below. Typically when it reaches about 1-1.5” up, the water starts to drain out of the tray valve. Capillarity (wicking action) of the block draws the solution towards the top of the block.

This is a good choice when growing smaller plants that remain in a smaller volume of substrate for the duration of their lifespan. This could be a 4” GRO-BLOCK or a 4” plastic pot with clay pellets surrounding a Grodan starter cube. Using a growing media height of 4” or less allows the water level in your ebb & flood system to reach up far enough for the growing media to be fully saturated during each

irrigation cycle. If using a taller growing unit, the top will remain drier and simple capillary action will draw the salts to the top of the block. You will have less algae, but this method requires top watering once each week in order to flush any salt build-up from the top.

What are the advantages/disadvantages of each?DRIp IRRIGaTION

• ADVANTAGE 1: It spreads out in the block and forces the old depleted nutrient to drain out. Position the drip stake so that the drip lands close to the stem, but without hitting the stem (as this can cause stem rot). In strong light a plant remains more active (faster growth) if you water a little at a time, but quite frequently.

• ADVANTAGE 2: You can control the amount of water you deliver each cycle. Refer to our tri-fold leaflet, “Growing Huge in Grodan” for drawing and further explanation of a drip system.

• ADVANTAGE 3: You can measure if you need to add on more irrigation cycles. Use a syringe to take a water sample from the block right after the last cycle of the day . If the E.C. or pH is too high, add an extra irrigation the next day.

EBB aND fLOOD

• ADVANTAGE 1: It is quick to set up—especially if you have several blocks/plants. Refer to our tri-fold leaflet, “Transplanting” for drawing and additional explanation of an ebb/flood system.

• DISADVANTAGE 1: With Ebb & Flow (Flood), the blocks are fully saturated during each cycle, so there is no way to control the amount of water.

• DISADVANTAGE 2: During this process, the old, depleted nutrient in the block is only partially flushed out. To help flush out old nutrients, we recommend top watering the blocks once per week.



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Ebb and Flood Example Step 1. If grow tray is 60” x 60”, empty tray will hold:

60” x 60” x 1” = 3,600 in 3

Step 2. To determine the required fill volume:0.5 x 3,600 = 1,800 in 3.

Step 3. Then, convert this to gallons: 1,800 in 3 / 231 = 7.8 gallons

Step 4. To determine a 10-minute fill time:

7.8 gal/hr. X 60 = 468468 / 10 min. = 46.8 gph

The pump will loose slight pressure when it lifts the water up to your grow tray. Loss of pressure means that the GPH will be a little lower that indicated on the pump package.

TIP: If you require more that 6 ft. of growing area, the easiest way is to add an extra pump in the reservoir and build a system on the opposite side of the reservoir. This will ensure that all your plants get enough water.


Determine pump size and irrigation particulars EBB aND fLOOD

For this type of system the fill rate must be calculated. Preferably the pump should be able to fill the tray in about ten minutes.

1. To determine the volume of water required, multiply the length (inches) by the width (inches) and assume a water fill height of 1 inch. This will give you the cubic inches of water that your empty container will hold.

2. Now multiply this number by 0.5 with the assumption that ½ of this volume will be absorbed by the plants. This is the required volume of water for your container.

3. Convert this number into gallons by dividing by 231. Size your pump so that the rate is at least equal to the required water divided by fill time. Remember, this number is in gal/min.

4. To convert to gal/hr., multiply by 60. Then to determine a 10-minute fill time, divide by 10.

DRIp IRRIGaTION (TOp waTERING)

For this type of system what matters most is the pressure (psi). The popular small pumps that retail for around $100 (such as Maxi Jet, Little Giant, Ecopro) do not generate enough pressure as they are typically only 2-6 psi. When the pressure (psi) is too low, drip emitters will either not drip at all, clog up really fast, or output less then the rated flow.

For small systems, it is possible to use a small pump and still get the benefit of top watering. Try this:

1. Do not use a drip emitter - instead use a drip stake that is not dependant on much pressure.

2. Attach ¼” tubing to the stake and stick the other end of the tubing with your ½” tubing. For a tight fit use a barbed insert. If necessary, seal with silicone.

3. Be sure to perform a test run with your timer to determine approximately how much water each plant receives during each irrigation cycle. Digital timers are best for scheduling short irrigation cycles.

Size of system Small pumps can raise water about 1.5 feet up and no more than 6 feet out. The greater the distance, the less water the plant will receive. See the tri-fold “pH and Watering” for guidelines on irrigation frequency and amount.

Using drip emitters (½ gph, 1 gph etc)The smallest pump to use with drip emitters is one that generates 10

psi. Look for a submersible pump that is about 1/3 HP. The great advantage with pressure regulated drip emitters is that all your plants will receive the same amount of water. For set-ups involving 20-30 plants, this is by far the best choice, as it is what many commercial greenhouses use.

For further information, watch our video ‘Drip system’ on grodan101.com.

Understanding Basic Irrigation Systems, cont.

Select a pump that is slightly larger than necessary, to create a by-pass that will allow direct some of the water to the Ebb & Flood table while the rest of the water empties back into the tank. This will keep the fertilizer well mixed and also aerate the water.

Two ball valves (incorporated into the by-pass) would enable the adjustment in the direction of the flow. This also allows you to change the fill rate of the tray.


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Maintaining a Successful Hydroponic SystemKeep the growing environment cleanClean the grow room beforehand. Also, before setting up your system and putting it back in the grow room, clean the plant box well with a 10% bleach solution. Always cut off dead leaves and remove them from the grow room. Decaying organic matter attracts fungus gnats. Also remove diseased plants so the infection does not spread.

When changing reservoir water, wash the tank well with a 10% bleach solution. If you use big trays for GRO-BLOCKS and GRO-SLABS, wash them too, especially if you have had a problem with root rot.

• DRIppERS. If you use a drip system, buy a few extra drippers, so you can change drippers if any are clogged. To clean them, throw the clogged drippers in a bucket of white vinegar.

• EBB/fLOOD SYSTEMS. Purchase a timer which can be set at five minute intervals, so a full cycle will only soak the stonewool for 10 minutes. To avoid salt built up, top water the plants once each week, using the same solution that’s in the reservoir. Never top water with plain water because it will shock the plants. Also be sure to have a tray with deep enough grooves so that water drains away from the Grodan cubes/slabs.

Changing reservoir solutionWe recommend that you completely change the solution once a week. Yes, you can top up the reservoir and adjust EC/pH, but your solution may have depleted its vital micro nutrients or be infected with Pythium (root rot). If your reservoir

contains ready to use (diluted) nutrient solution, use phosphoric acid (pH Down) or lemon juice to lower the pH. The recommended temperature in the tank is 65-70⁰ F (18-20⁰ C). Typically, the temperature inside the rockwool will be about 2⁰ degrees higher than tank temperature. If temperature inside the rockwool reaches 78⁰F (26⁰ C), then the risk of disease and root rot is very high.

Watering tips Download the blue leaflet “Watering and pH” from our Website or pick up one from your local retailer.

When using top drip irrigation, the best way to determine how much to water is by testing EC (ppm) inside the block. The result will determine when the next water cycle should start. If E.C. or pH is too high, add another water cycle to the day.

If using an ebb & flood system, the measurement inside the blocks will always be slightly off because the blocks do not get flushed during each irrigation.

• We prefer EC measurement, which measures strict SALT where as ppm measure any particle (parts per million).

• Allow the amount of drain water to dictate how much you water. During a full day of irrigation, if you have less than about 25% water draining from the blocks, then add an extra irrigation cycle. This does not mean extend the time of a cycle, but rather add in an extra cycle. With strong light and fast growth, it is best to feed your plants like a marathon runner - in short frequent cycles.

Watch pH level Never allow the nutrient solution to fall below pH 5 or the stonewool may be damaged. If your nutrient solution is below pH 5 or above pH 7, plants cannot readily take up nutrients. Before planting, always saturate the stonewool with pH 5.5 water. Flush Grodan with your nutrient solution at pH 5.5 and drain to waste and then put the Grodan in your system. The pH in your reservoir will increase during vegetative growth. This is a natural response and means the plant is growing! But also higher temperature and algae growth in your reservoir will cause pH to go up. So keep an eye on pH. For most plants, the reservoir should be around pH 6.0.



Understanding the basicsFirst, read section entitled “Maintaining a Successful Hydroponic System”. In this, we emphasize the importance of evaluating the overall appearance of your plants on a daily basis. Then, should any challenges arise, refer to the tables provided on the following page to help trouble shoot and find appropriate solutions.

Understanding the basics about a plant’s life-cycle is helpful. For example, there are basically two stages in a plant’s life:

• A vegetative (leaf and stem growth) and

• A generative (bloom and fruit growth)

A plant should always have a good balance between the amount of leaves and the amount of blooms or fruit. Consider the tomato plant. If there are too few leaves, the plant will not make enough photosynthate (sugars), reducing the availability of sugars and water flow to the flowers and growing fruit. The results are smaller and possibly fewer fruit.

Keys to effective trouble-shooting When using the tables (on following page) as a tool for trouble shooting, do not change all the parameters at once. This will result in the plant becoming too vegetative or too generative. Choose the parameter that differs the most from the table and adjust only that one.

Then, wait a few days to see if that has solved the problem. If this alteration does not perk up the plant, then find the next obvious parameter to change. It is almost like making soup. If it doesn’t taste good, you don’t mix in a number of ingredients all at the same time to make it taste better. You add a little bit of one, then taste. Then, you might try another if it didn’t work. You apply the same idea when you encounter a problem with your plants.

Greenhouse tomato - during vegetative stage

Greenhouse tomato - during generative stage

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Maintaining a Successful Hydroponic System, cont.


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successful growingTaBLE a - VEGETaTIVE STaGE

During the night when the grow light is off, the humidity will naturally increase slightly as the air cools. This is not a concern. Just maintain the 70º room temperature and the slab water content during this time.

When growing plants in a closed room, CO2 will measure around 300 ppm due to plant respiration. Therefore, for vegetative growth there should be little or no CO2 injection.

TaBLE B - GENERaTIVE STaGE

NOTE: Do not inject CO² at night.

The figures in the above tables should be viewed as rule of thumb only. They are based on tomato plant responses to changes in the environment inside under grow lights. Greenhouse and out door environments will of course have some different parameters and others that can not be managed.


Trouble-Shooting Reference Chart

PARAMETER Grow light

12 hours/day 1000 W bulb


HUMIDITY (AIR)

80 %

75 %

CO2

400 ppm

300 ppm

Reservoir temperature

65-70 F or 18-20 C

65-70 F or 18-20 C

Room Temperature

(Day & night) 70º

(Day & night) 70º

E.C. (Electric Conductivity)

2.5

2.0

H2O content in Grodan

(Day & night) 75%

(Day & night) 75%

PARAMETER Grow light



HUMIDITY (AIR)

75 %

70 %

CO2

750-1000

ppm

500-750 ppm

Reservoir temperature

65-70º F or 18-20º C

65-70º F or 18-20º C

Room Temperature

Day 75º F Night 70º F


E.C. (Electric Conductivity)

2.5

2.0

H2O content in Grodan



Pepper production with GRO-SLABS™ in greenhouse.

SUCCESSFUL GROWING


Learning from your own experiencesConsider keeping a plant journal to keep track of the EC, pH, temperature, CO2 and light level each day. This way you can learn from your own mistakes and successes. Records like this also make it easier for your local retail shop to provide the best solution for you, should a problem arise. Make a habit of examining your plants every day. Do they look perky? Inspect leaf color, shape and texture. Look closer, do you see any bugs? Afterwards, update your journal. It’s easier to correct a problem if you catch it early

on. Before blaming your plant food for unhappy plants, check your journal. Everything must

be in balance. Change one parameter at a time and evaluate the effect.

• A common error is the reservoir water is too warm. If so, use a chiller to maintain around 70⁰ F (20⁰ C).

• If the plant fails to set flowers/fruit, increase the difference between night and day temperature. If that is not efficient, increase CO2 injection during the daytime.

CAUTION: Be careful in accepting the advice of friends and other hobbyists. What worked for them may not work equally well in your growing environment. Experience is the best educator.

Minimizing Potential ProblemsIdentify and Solve Common Problems

Before a solution can be found to a problem, one must first learn to correctly identify the problem. The following pages contain sections about the most common problems that one may encounter. Both the diagnosis and a

solution are provided. We hope that this section will help you address any issues so that you may in turn help others in kind.

The most frequent questions we receive from hobbyists involve the following issues:

• Unhappy, slow-growing plants

• Calcium deficiency - leaves curl down

• Cuttings are not rooting

• Seeds sprouted but turned brownish

• Mildew (two types)

• Algae (keep it in check)

• Stunted plant growth

• Abnormal, irregular leaves

• Soft bodied pests


SUCCESSFUL GROWING

Good ideas to consider: • Keep a plant journal• Check reservoir temperature• Inspect plants closely


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DETaILED DEScRIpTION

Purple stems, yellowing, root pack much less dense. The roots barely use 25% of the Hugo block. Block stays consistently heavy, and the watering schedule recently changed from daily to every other day.

ExpLaNaTION aND SOLUTION

The lack of roots is the main reason your plants look the way they do. The problem started with your seedling.

• About 75% of the root mass is established when the plant is young.

• The roots will get longer/thicker later but the all the roots hairs must be established by the young plant. This is why we say that ‘healthy baby’ is the way to success.

Why didn’t healthy roots develop in the early stage?

• 99% of the time, your rockwool was kept too wet.

• The chloramine in your tap water could also have been too high. This can limit root growth, but not likely kill the plant. Talk to your local store about a carbon filter if you suspect chloramines, or use bottled water for your irrigation needs.

ThE EaSY fIx

Since it’s easier to manage the water content in a smaller block, transplant the 1.5” cube to a 3” block first, then put the 3” onto Hugo.

For successful transplanting,

• Mist the 3” block twice daily but don’t water until the block feels light (about half weight).

• When transplanting the rooted 3” plant , use a stake to hold it firmly to the Hugo.

• Water the 3” block (low volume, twice daily) until rooted into Hugo.

aNOThER OpTION: KEEp YOUR cURRENT SETUp

• Change your watering early on. The seedling in 1.5” A-OK Cubes must be healthy, with roots that extend about 1” below the cubes for best results.

• After transplanting to the wet Hugo; Only MIST (plain water) twice daily for the first week.

• AVOID watering until you can feel that HUGO is lighter or the upper part starts to dry out. Then water sparingly – right on the little cube – probably about ½ cup.

• Once you see active growth and the cube has rooted into Hugo, then slowly increase the water volume. Do NOT drown them!

What in the World is Wrong with My Plants?

“I’ve sprouted seedlings in A-OK Starter Plugs then transplanted them directly into a Hugo block. Now, my plants look crappy and are growing very slowly.”

OMG - what’s wrong with my plants?

So you’re saying I’ve got Root Rot... and it’s THAT serious?

OK, so I may have been over watering, so what should I do?

Next time, I’ll be taking preventative action, for sure!

Thanks, Grodan!

SUCCESSFUL GROWING


RULE 1: ExcLUSION

• Fungal spores can come from anywhere including tap water.

- Spores can survive in microscopic amounts of water or even be airborne.

• Sanitize the growing area.

- Bleach will kill fungal spores but always allow everything to fully dry before setting up again.

- Always clean stock tanks and equipment, and quarantine any new plant material until you are certain it is disease-free.

RULE 2: DRaINaGE

• The most common cause of root disease is over- watering. So, reduce watering in order to strengthen root growth.

- For drip irrigation, lower the duration.

- For flood irrigation, lower the cycle frequency.

RULE 3: hEaLThY ROOTS = SOLID fOUNDaTION

• Roots almost always indicate symptoms of root rot before the leaves will.

- Roots should be a healthy white color.

- Nutrient solution can darken roots but dark roots lead to problems

- Slow growth can be an indicator of root rot. (see back page)

Understand and Avoid Root RotRULE 4: DON’T paNIc

• Anyone can experience plants with root disease - you are not alone.

• There are many fungicides (even some organic)available to use for this purpose. Be sure to read the label carefully - whether using organic or not.

• Immediately remove all affected plants from your main growing room.


“An ounce of prevention is worth a pound of cure” ... at least!

RULE 5: pREVENTION

• Prevention is always the best way to avoid root rot and much easier than treating an outbreak.

• Consider adding a preventative water soluble fungicide to your tank.

• Avoid over watering.

- The water content of Grodan GRO-BLOCKS should reach about 50% BEFORE initiating the next watering.

- Never irrigate when the lights are off and aim for 50% water content in the blocks before turning the lights off.

• Make sure to establish quality root mass during propagation (see back page).

• Maintain an ideal temperature in the stock tank.

- Temperature should stay around 64°-69° F (18°-21° C). If the tank water reaches 75° F (24° C) the risk of root rot increases exponentially.

- Temperatures that fall below 60° F will stunt the plant growth.

• Always provide sufficient drainage.

SUCCESSFUL GROWING


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successful growingPROBLEM: Cuttings are not rooting• Diagnosis: Your tap water has too much

chloramine (plant toxin). Chloramines are used by a number of water treatment plants and therefore also frequently found in tap water. Chloramines kills beneficial bacteria in the root zone. But more importantly, chloramines are very dangerous for plant growth and will spread toxicity to the plants very easily.

• Solution: Use a carbon filter on your tap water before using on the plants. Feeding with chloramines is just as dangerous with flood water as it is with drip irrigation. A carbon filter will definitely solve any issues. There are shower heads available that also removes the chloramines. Alternatively, use bottled water for your cuttings/seedlings.

PROBLEM: Seeds sprouted but turned brownish• Diagnosis: If you used the right water (see

above) then this is most likely pythium (http://en.wikipedia.org/wiki/Pythium) which causes Damping Off (root rot). Pythium can kill seedlings overnight. It is a fungus that is found naturally in many soils (and peat). In wet, warm, stagnant water conditions - it will cause damage to seedlings trying to grow in Grodan.

• Solution: If you have a persistent problem with Pythium; add a fungicide (only use 10% of recommended strength) to your water.

SUCCESSFUL GROWING


Identify and Correct Problems

• Diagnosis 1: If the youngest leaves curl downward, often it indicates a calcium deficiency. If old leaves are curled; something is probably wrong in the root zone (which also reduces the calcium uptake).

• Solution: Lower the humidity in your grow room. Add fans to improve air circulation

• Diagnosis 2: Another cause of BER or obvious Ca deficiency in the leaves is due to poor root development. This is a result of (A) low substrate temperatures or (B) the presence of a root pathogen such as Pythium or Phytophthora. Calcium is taken up by the area of the root immediately behind the root-tip. If the roots are not actively growing, new root tips will not form and consequently, Ca uptake will be reduced.

• Solution a: For low substrate temperature, increase reservoir temperature to about 68 F (20 C). If outside, set a heat mat to the same temperature and place it under the slab.

• Solution B: Pythium becomes a problem if the slabs are kept too wet at night. Stop irrigation in good time so that the slab water content can lower to about 55% before the lights turn off.

PROBLEM: Calcium deficiency (leaves curl down)Calcium deficiency is the result of insufficient water movement through the plant. Calcium only travels in the water stream of the plant, not in the nutrient stream. Therefore, calcium deficiency is usually related to the climate in the growing area. High humidity will prevent calcium uptake even if there is sufficient Ca in the feed solution. Also, large humidity fluctuations between day and night will disrupt the Ca flow within the plant and lead to blossom-end rot (BER).

Ca deficiency in leaves Ca deficiency in fruit


PROBLEM: Algae growthAny time there is a light colored surface moist with nutrients and water, there will be algae growth. Algae are not harmful to the plant, but excess amounts of algae (especially dead “black” algae can attract fungus gnats. For this reason, it is best to minimize algae growth. Extreme algae growth can cause nutrient solution from the drip emitters to run off the GRO-BLOCK, instead soaking into it.

• Diagnosis: When there is excess amounts of algae growing on the top of the block, fungus gnats and shore flies lay their eggs in the algae and the larvae that hatch will feed on the algae. When the population of the fungus gnats get very high the larvae can even attack the roots and can cause a secondary infection of Pythium (root rot). On the other hand, shore flies will not feed on the root but will leave their feces all over the plants/fruit.

• Solution: CUBECAP® plastic covers works great to almost eliminate algae. They will keep will keep the temperature of the bock higher in hot weather due to lower evaporation so be sure to keep your reservoir at no more than 70 F (21 C). Too high temperature can cause bacterial infection. If you are running into problems with bacterial infection; Once the blocks have rooted well into the slabs or potting mix– move the drip tube down beside the block. The drier top will help avoid bacterial infection.

PROBLEM: Stunted plant growthUnhealthy plants exhibit stunted growth as a result of a weakened root system.

• Diagnosis: Temperature of reservoir measured 79 F (26 C). A temperature this hot weakens the roots making them susceptible to all fungi & diseases – and can cause devastating problems. Typically reservoir water should be a few degrees colder than the maximum above – so 18-23 ( 65-73 F) because the water typically heats up some once it enters the slab or block.

• Solution: maintain a temperature inside rockwool between 59-70 F. (The ideal is 65-70 F (18 C -21 C) Any lower than 59 F and it can stunt plant growth.

SUCCESSFUL GROWING

Identify and Correct ProblemsPROBLEM: Mildew (two main types)There are two main types of plant mildew; powdery, and downy. It is important to know the difference.

• Powdery mildew: notice white ‘spots’ on the top surface of the leaves.

• Downy mildew: notice yellow wilted spots on the top side of the leaves, but this kind actually lives under the leaf.

Mildew can be very difficult to kill. Even if you clean your room meticulously, your next crop is still susceptible because spores float through the air and can land on new plants to infect them as well.

• Solution - Step 1: Remove your old plants. Then, leave the room undisturbed for 24 hours (so the spores settle on the surfaces). Now go in and spray the whole room with a pesticides for Mildew. Finally, use a 10% bleach solution and wipe down/clean the area thoroughly.

• Solution - Step 2: For your daily maintenance, check all plants for any sign of mildew. If you notice any, immediately spray both the infected plant and its closest neighbors. Spray on top of the leaf for Powdery Mildew and spray under the leaf for Downy Mildew.

High humidity increases mildew problems. So always have fans blowing to provide decent air circulation throughout the entire room.


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SUCCESSFUL GROWING


Tomato spotted Wilt VirusPROBLEM: Abnormal or irregular leaves

UpwaRD-cURLING LEaVES • Diagnosis: This could be as a result of too

much light on the plant. Leaves will curl up to protect themselves if light is too strong or lasts too long.

• Solution: Raise the grow light up 6-8 inches. If outdoors, use a shading cloth between the hours of 10 am - 2 pm when the light intensity is strongest.

wILTED TOp EDGE Of LEaVES • Diagnosis: When top leaf edge is wilted,

typically it is a result of too rapid change in the morning. Your room might be warm when the light goes on—but the plant is still cold.

• Solution: Start your heaters about 1 hour before your light comes on.

BUBBLING LEaVES • Diagnosis: If the temperature is too low, leaves

will display a slight bubbling rather than curling.

• Solution: For most plants, try to maintain an environment temperature between 65-70 F (18 C - 21 C).

BRITTLE, DIScOLORED LEaVES • Diagnosis: Brittle, discolored leaves could

be caused by Tomato Spotted Wilt Virus, transmitted by thrips. Normally, this is only a problem if you are in close proximity to other growers or if you are growing outside.

• Solution: Thrips are fairly easy to kill and many remedies are available. However, preventative care is best. Spray plants from day one with something like an organic insecticide (soap). Typically, thrips can be managed effectively and safely by spraying 1-3 times per week.

PROBLEM: Soft bodied pests (like aphids)• Diagnosis: Noticeable unfamiliar, soft-bodied

pests found on plants.

• Solution: When you have problems with soft-bodied pests, here’s an inexpensive remedy. Add 5 grams of baking soda to a liter of solution and spray with that. You can repeat this procedure for up to 3 treatments - but not more as it could damage the plant. Drain to waste with each treatment. The baking soda dries out bugs (like aphids), killing them.

Identify and Correct Problems

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