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Wellington Fields Allotments - Hixon.


Plough Field Allotments at Amerton

Gardening Tips
By Mrs FM

Unusual & Old
Fashioned Fruit

Herbs & Other
Edible Plants.

Environmental Issues And Going Green.

Vines And Other Climbing Plants.

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Books By
Alan J Hartley



Propagation Special.

With the Spring nearly upon us I have been thinking about seed sowing that will soon begin in earnest. A lot of Allotmenteers buy their vegetable seedlings ready growing, but I usually start mine off at home as we can’t have greenhouses on the Allotments, nor have we got electricity up there anyway. You can start a few seeds off in pots that are sealed inside plastic bags and put on windowsills, and this is all right for a few seeds, but an unheated propagator is much better. It will lift the temperature inside it quite a few degrees, but perhaps more importantly, will not only raise the humidity levels, but will also keep the soil from drying out too quickly. Heated propagators of course are even better for seeds and much cheaper to run than trying to heat the whole greenhouse. Typically an electric greenhouse heater will be 2, or 3 KW for even the smallest greenhouse, whereas a heated Propagator may be only 50w for a bought, plastic job, or 75w for a homemade propagating bench using a soil warming cable. 
The current cost of electricity is about 12p per k.w.h. which works out to around 2p per watt, per week. Consequently a 3kw fan heater on constantly would cost around £60 per week and a 75w heating cable £1.50 a week. However, with a thermostat these running costs are both dramatically reduced, but it does show how much cheaper it is to heat a small propagator rather than the whole greenhouse. Small electric propagators typically start at about £25 and run at 50w, heating 2, or 3 small seed trays inside. Some come with a fixed, preset, thermostat and their costs vary widely with better quality Propagators having adjustable Stats that can push their price to well over £100. I remember when I was a company rep’ over 35 years ago selling greenhouse equipment and we used to sell one that cost £200.This was when my wages were £60 per week! Talk about luxury goods!

However, it is much more cost effective to make your own with a Soil Warming Cable than buying a pre-made Propagator. Again, Cables are cheaper to run with a ‘stat whether it is fixed, or not, but you do have to make your own propagation enclosure on a bench. With this in mind they have just made me a new propagation bench at work to relieve the pressure on my little greenhouse at home and prevent the struggle I had with all the seed sowing I did for them last year. We are using an open heating cable at work, but you can buy heating mats that are simply the same cables already enclosed in layers of foil so that they are neatly spaced out for easy use. Of course, they are more expensive though.
Cables generally cost upwards of £20, although bigger ones don’t cost much more than a small one and thermostats are roughly £30, or £40. 
A 20ft, 75w cable might heat a bench for about 10, or 12 seed trays @ £1.50 per week with bigger sizes running at 40ft and 150w, and 80ft at 300w. These 3 are the most popular sizes, but there are other lengths both bigger and sometimes smaller.

There are other ways you can heat a propagator as you can also buy heat lamps that are often used by Pig Farmers and Cannabis growers!
Commercial plant growers use this type of artificial lighting unit to bring things on out of season and in the old days they were run using big Halogen bulbs for both heat and light, but they were very expensive and there are now, new, much cheaper to buy and cheaper to run, L.E.D. light systems.

Of course, a Propagator is not only good for raising seeds, but also good for rooting many types of cuttings. A little “Bottom Heat’” as they say, works wonders. For the really enthusiastic grower you can even buy mist units to help cuttings root, the same as Commercial growers use, but few amateurs could justify the cost. We haven’t even got one at work, although the subject has been broached, so who knows, we may get one yet for all the shrubs that I am supposed to be growing for them in the future!


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