HOT BEDS

JACK FIRST

How to grow early crops

using an age-old

tecHnique

“�Jack�is�a�fountain�of�knowledge�and�the�expert�on�hot�beds.�When�I�visited�his�allotment�and�saw�how�advanced�and�healthy�his�crops�were,�it�proved�to�me�that�these�ancient�old�systems�still�work�a�treat�and�are�just�as��relevant�now�–�if�not�more�so�–�than�they�ever�were.” Joe Swift, garden designer and TV presenter

£9.95

Distributed in the USA by Chelsea Green www.greenbooks.co.uk

Printed in the UK on paper sourced from responsibly managed forests, using

vegetable inks

Hot beds are nothing new: they were used by the Victorians and by the Romans. By reviving and modernising this ancient vegetable-growing method, Jack First produces healthy plants that crop at least two months earlier than conventionally grown vegetables, even in his native Yorkshire.

This practical, illustrated guide has everything you need to understand how to use this highly productive, low-cost, year-round, eco-friendly gardening technique. Straightforward explanations and diagrams show how the natural process of decay can be harnessed to enable out-of-season growing without using energy from fossil fuels or elaborate equipment.

With just stable manure (or alternatives), a simple frame and a small space, you can be harvesting salads in March and potatoes in early April.

Jack First is an experienced horticulturalist who has pioneered, developed and fully tested the hot bed methods described in this book. He works with volunteers on a large plot in Keighley and is the sole supplier to his local food cooperative of out-of-season greens, new potatoes and salads.

HO

T B

ED

SJA

CK

FIR

ST

Chapter 1

hot beds are nothing new

not missed by the Romans. The gardeners of Tiberius (42bc–ad37) had a problem, as their emperor demanded salads out of season. They built beds of stable manure and placed frames upon them. Soil was put inside, and the frames covered with thin sheets of ‘talc’ (translucent sheets that let light through). The manure warmed not only the soil but also the air in which the crops grew.

The problem of growing crops early in the British Isles and other temperate zones was pondered and answered at least two thousand years ago. If you have ever looked at a stack of stable manure on a cold day, you will have noticed that steam is visible. Clearly there must be a heat source, and this is a fact that was

Chapter 1 Hot beds are nothing new 11

A hot bed is a warmed, protected environment, created by heat generated from decomposing organic matter, used for producing early crops.

In fact, hot beds of some form were probably in use before the Roman era, as animals were domesticated thousands of years prior to this period. Humans lived in close proximity to their animals, often directly above them in the same building, where they benefitted from the warmth of the stock. Seeds in horse feed readily pass into the dung, and hay containing seeds is often mixed with the litter of other penned animals. This litter, probably also containing food scraps thrown down from the household above, would have been taken from a pen or stable and stacked outside, much in the same way as is practised today. Our ancestors would have beheld the bewildering sight of germinated seeds growing on the fermenting stack when all around was covered in snow or ice. Perhaps, in the pre-historical era, this revelation led to the first hot beds. In those harsh times the ability to grow early crops would have considerably improved survival rates.

Down the years many nations have understood and adopted this principle. Up until the First World War Parisian market gardeners were masters of this art, supplying not only their home market with early crops but that of Covent Garden too. One of the French methods,

16      Hot Beds CHAPTER 2   How hot beds work      17 

Hot bed basics or more. It gradually cools over a period of several weeks or even a few months. The higher the stack, the longer the heat will last.

We also know that these microorganisms require air and moisture, and that a shortage of either will reduce or even prevent decomposition. Too much water will not only cool the manure but also drive out the air that these microbes need. Given the right conditions, a hot bed will pro-duce heat over a long period. More importantly, although the tempera-ture slowly declines, heat is released both day and night. As the microbes’ food supply is exhausted, the heat gradually fades. At this point earthworms enter the manure and not only aerate it but also increase its fertility by way of their casts.

Armed with this information, our aims when making use of hot beds are as follows:

l To manage the manure in such a way as to create ‘bottom heat’ in the bed.

l To manage that heat over as long a period as possible.l To use it when it is most needed, and that is from January to April,

while light levels are increasing.

The main principle to remember is this: the hot bed’s decline in tem-perature must coincide with the longer days of mid- to late March. By this time the worst of the weather should have passed and longer, warmer days and shorter nights are compensating for the loss of heat in the manure.

The growing frame sits on the manure, part-filled with soil or compost, with a cover of glass or polythene. The frame is usually made of wood with a thickness of at least 2.5cm (1"), which helps to retain the heat and keeps out frost. The cover, known as the ‘light’, ‘or ‘lights’ if more than one, also retains heat and keeps out rain and snow. The growing medium – the soil or compost – inside the frame is thus kept warm, moist and not saturated, and the air within the frame is also warmed by the constant heat rising from below. Ventilation is provided by raising or removing the light.

In essence:l The stable litter or other organic material used in the hot bed drains

well, so the growing medium above it also drains well.

Side view of hot bed with growing frame and light. The outer frame should be at least 180cm × 180cm (6' × 6'); the growing frame at least 120cm × 90cm (4' × 3').

76      Hot Beds CHAPTER 6   Planning and sowing      77 

January

l Turn the old hot bed again or purchase compost in readiness forframes.

l If you aremaking large hot beds, continue to purchase or collectmanureuntil themiddle of themonth. Ifmakingsmallhotbeds,collectorpurchasealoadofmanureattheendofthismonth.(Largehotbedstakelongertobuildsoyouneedtoallowmoretime!)

l Makeupthehotbeds, largeorsmall, in the lastweekofJanuary,withtheaimofsowinginthelastfewdaysofthismonth. Makesureyouallowadequateheightofhotbed,asitwillneedtoprovideheatforseveralmonths.

l Forasmallhotbed,sowacombinationofcarrots,spinach,radishand rocket or salad leaves, or, if lettuces have been grown fromOctober,planttheseoutandomittherocketorsaladleaves.

l Ifyouhavealargehotbedwithmultipleframes,includetheabove-mentioned crops andalso sowor plant potatoes, beetroots, onionsets,lettuces,turnipsandspringonions.

l Ifyouareplanningahotbedwithalternativematerials,waituntilnextmonthbeforemakingit.

February

l Ifanyof theJanuarytaskshavenotbeencompleted, thendothemearlyinthemonth.Germinationwillbefast–givemoreairwhennec-essaryandonfavourabledaysremovethelightsforshortperiods.

l Februaryisoftenthecoldestmonth,sokeepbubblewrapclosebytoinsulatewithifnecessary.

l Keepaneyeonwatering,assomecropswillbegrowingawayattheendofthemonth.

l Sowearlyleeksonavacantbed.l Ifyouaremakingahotbedwithalternativematerials,itcanbedone

attheendofthismonth.

March  

l MakealternativehotbedsinearlyMarchifyouhaven’talreadydoneso,andsowupasforaJanuaryorFebruarysowing.

l Plantpotatoesinpotsifyouwish,forplantingoutinApril.l Previouslysowncropswillrequiremoreairnow;therewillbemore

favourabledaystoremovethe lights,but theymustbereturnedatnight.

l Morewaterisrequired,soallowraintoenterthehotbed.Ensurethatthe lightsareclosedagainatnightandprotectiongiven if frost isforecast.

l Earlyinthemonthstartharvestingradishes,rocketandsaladleaves.LettucesplantedinlateJanuarytoearlyFebruarywillbereadylateinthemonth,aswillturnipsandoccasionallypotatoes.Bewaryoffrosts,particularlywithpotatoes.

l When gaps appear, sow more radishes, rocket, salad leaves andspinach.

Late March: rocket has been harvested, making room for carrots and other crops. Leeks are to be planted later, between carrots.