evaluating the soil in your raised bed
TRANSCRIPT
Soil preparation
• Evaluating the soil in your raised bed and the organic matter you are using to top your bed up with.
Raised bed soil
• The base of the raised bed will sit on a certain soil type. As indicated.
• Most soils are loams which are a mixture of sand, silt and clays organic matter and air.
Loams
• Loams are named according to the main textural class present.
• The 3 broad groups are• Sandy loams • Loams• Clay loams
preparing your base soil
• Firstly mark out your bed and then turn the soil over with a spade or shovel.
• Check the depth of the soil. Ideal at this stage is if the soil is dark, friable, and 30-40cm deep.
• If not fork over the bottom of the trench or double dig.
Evaluate your soil texture
• A simple way to check soil texture is to moisten the soil and form it into a ball or worm shape and then press it with your thumb.
• The way the soil deforms tells you its texture.
• You can also use a feel test.
• Soils of different textures also feel different .
• Sands feel gritty• Clays feel smooth and
slippery, and • Loams sit in between
Sandy loams
• Sandy loams don’t hang together well and wont easily form a ball or break up easy when you try to roll them into a worm shape.
• They don’t hold water well and are normally low on nutrients
Clay loams
• These soils are yellow to brown, they form a ball or worm well and when you press them you leave a clear imprint of your thumb
• Clays are high in nutrients but these soils bake dry in summer and flood in winter because of their fine pore spaces
loams
• These are the best soils for gardening on they are made up of
• 40% sand, 40% silt and 15% clay and 5% organic matter.
• When you roll and squeeze them they deform but don’t break apart
Soil structure
• This describes the way your soil hangs together.
• An ideal soil structure for growing vegetables is one that is described as friable. This means it breaks up easily into a crumbly form .
• A simple shatter test will tell you what sort of structure your soil has.
• Take a spade full of soil and drop the back of the spade onto the ground, the soil on top will beak up, shatter.
• Different soils behave differently.
Shatter test sandy loam
• Sands are loose and collapse when you try to cultivate them
• Note the way the block of soil has broken up and collapsed
Shatter test clay loam
• Clays are tight and blocky and are hard to break up and cultivate
• Note how they kept their shape and hardly broke up when dropped
Shatter test loam
• Loams break up well to form a friable soil which drains well but holds sufficient air and water.
• Note the crumbly friable nature of the soil after it was dropped
Adding to your raised bed.
• The advantage of raised beds is that you can easily add
• Topsoil• Compost• Potting mix • Dried manures• Or any combination of
the above to improve on the soil you already have
Adding compost 1
• Compost is ready for use when
• it has broken down and you cant tell what the raw materials were that made it up
• It is a dark colour• It is crumbly and full of
worms.• This is home made, why
would you buy it when you can make your own!!
Adding compost 2
• There are many types of commercial composts available for purchase.
• I Like Mushroom compost which has a wonderful spongy structure.
• Add all composts thinly and regularly working them into the soil with a garden fork.
• DON’T SNIFF them.
Adding Topsoil
• You can top your bed up with extra top soil. But it is hard to get hold of and expensive.
• Make sure you break it up well and thoroughly mix it into your existing soil.
• Check that it is weed free
• You can use dried animal manures to top your raised bed up. Like using compost light regular additions worked regularly into the soil gives the best results.
Adding manures