Hot Beds: How to Grow Early Crops Using an Age-Old Technique

7/29/2019 Hot Beds: How to Grow Early Crops Using an Age-Old Technique

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HOT BEDS

JACK FIRST

How to growearly crops

using an

age-oldtecHnique



Chapter 1

ho bds noing nwThe 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



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.

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 benetted 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 downfrom 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 rst 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

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, andthat 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.



CHAPTER 2 How hot beds work 17

Hot bed basics

The growing frame sits on the manure, part-lled 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 shouldbe at least 180cm × 180cm (6' × 6'); the growing frame at least 120cm ×

90cm (4' × 3').



76 Hot Beds

January

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

frames.

l If you are making large hot beds, continue to purchase or collect

manure untilthemiddle ofthemonth. Ifmakingsmallhot beds,

collectorpurchasealoadofmanureattheendofthismonth.(Large

hotbedstakelongertobuildsoyouneedtoallowmoretime!)

l Makeupthehotbeds,largeorsmall,inthelastweekofJanuary,

withtheaimofsowinginthelastfewdaysofthismonth. Makesure

youallowadequateheightofhotbed,asitwillneedtoprovideheat

forseveralmonths.

l Forasmallhotbed,sowacombinationofcarrots,spinach,radishand rocket or salad leaves, or, if lettuces have been grown from

October,planttheseoutandomittherocketorsaladleaves.

l Ifyouhavealargehotbedwithmultipleframes,includetheabove-

mentioned crops and also sow or plant potatoes,beetroots,onion

sets,lettuces,turnipsandspringonions.

l Ifyouareplanningahotbedwithalternativematerials,waituntil

nextmonthbeforemakingit.

February

l IfanyoftheJanuarytaskshavenotbeencompleted,thendothem

earlyinthemonth.Germinationwillbefast–givemoreairwhennec-

essaryandonfavourabledaysremovethelightsforshortperiods.

l Februaryisoftenthecoldestmonth,sokeepbubblewrapclosebyto

insulatewithifnecessary.

l Keepaneyeonwatering,assomecropswillbegrowingawayatthe

endofthemonth.l Sowearlyleeksonavacantbed.

l Ifyouaremakingahotbedwithalternativematerials,itcanbedone

attheendofthismonth.



CHAPTER 6 Planning and sowing 77

March

l MakealternativehotbedsinearlyMarchifyouhaven’talreadydone

so,andsowupasforaJanuaryorFebruarysowing.l Plantpotatoesinpotsifyouwish,forplantingoutinApril.

l Previouslysowncropswillrequiremoreairnow;therewillbemore

favourabledaystoremovethelights,buttheymustbereturnedat

night.

l Morewaterisrequired,soallowraintoenterthehotbed.Ensurethat

thelightsareclosedagainatnightandprotectiongiveniffrostis

forecast.

l Earlyinthemonthstartharvestingradishes,rocketandsaladleaves.

LettucesplantedinlateJanuarytoearlyFebruarywillbereadylate

inthemonth,aswillturnipsandoccasionallypotatoes.Bewaryof

frosts,particularlywithpotatoes.

l When gaps appear, sow more radishes, rocket, salad leaves and

spinach.

Late March:rocket has beenharvested,

making room forcarrots and othercrops. Leeks are tobe planted later,between carrots.



“Jackisafountainofknowledgeandtheexpertonhotbeds.WhenIvisited

hisallotmentandsawhowadvancedandhealthyhiscropswere,itproved

tomethattheseancientoldsystemsstillworkatreatandarejustas

relevantnow–ifnotmoreso–thantheyeverwere.”

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 theRomans. By reviving and modernising this ancient vegetable-growing

method, Jack First produces healthy plants that crop at least two monthsearlier than conventionally grown vegetables, even in his native Yorkshire.

This practical, illustrated guide has everything you need to understand howto use this highly productive, low-cost, year-round, eco-friendly gardeningtechnique. Straightforward explanations and diagrams show how thenatural process of decay can be harnessed to enable out-of-season growingwithout 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 haspioneered, developed and fully tested the hot bedmethods described in this book. He works with volunteerson a large plot in Keighley and is the sole supplier to his

local food cooperative of out-of-season greens, new potatoesand salads.

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Hot Beds: How to Grow Early Crops Using an Age-Old Technique