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Straw bale culture

Straw bale culture.

Originally developed for commercial greenhouse production to overcome
diseased soil in the days before the proliferation of hydroponics. If straw
bales are readily available the method is a cheep way of providing
sufficient bottom warmth and carbon dioxide to push young plants through
fluctuating early Spring weather when ground temperatures would otherwise
be too cold to plant in.

Standard size straw bales (1 metre, 3 foot,) are induced to heat through
the application of water and nitrogen fertiliser. You actually turn the
inside of the bale to compost for the plant to grow in as you go with this
technique hence its value in overcoming soil problems.

METHOD
Position the bale on its side in a trench or leave it exposed on the
surface, but remember this system requires a day-time temperature of 10C
(50F) in order for the fermentation to start. This means the bale should be
in a greenhouse or under the cover of a temporary cloche capable of keeping
heat in and draughts out. 

Start treating the bale about 2 or 3 weeks before the intended planting
date by soaking it repeatedly with water (warm water if you can). When it
is saturated pour on a good hefty dose of a nitrogen-rich water soluble
fertiliser and water it in. Remember it is only the nitrogen in the
fertiliser that is needed to fuel the fermentation. If your bale is too
tightly packed it may initially repel water - hammer a few holes with a
sharpened stake.

After 3-4 days apply another dose of nitrogen fertiliser and water it in.
Provided the bale is sufficiently wet and the temperature high enough the
bale will now be getting warm.

In another 2 days apply a good soaking of a slow release (organic)
fertiliser. By this stage the bale is really hot in the middle. 

Wait until the internal temperature shows signs of dropping then lay a
ridge of potting mix 13cm (5ins) deep on the top of the bale. In a day or
two set out two tomato plants with their roots just covered by the potting
mix. The plants quickly root into the bale.

POTENTIAL PROBLEMS...
Watering - It can be difficult to water tomatoes grown in bales because of
the difficulty in knowing what is happening inside. I use a moisture probe.

Feeding - Fermentation reduces the amount of nitrogen available to the
plant. This process diminishes over time which means you may think you are
applying a well balanced fertiliser but what your plant actually gets is
somewhat unpredictable. Personally, I try never to get neurotic enough to
agonise over this kind of thing.

Burns - If you put the plants in too soon, before the fermentation starts
to weaken, you can damage the plant's roots.

IT'S NOT HARD
In summary all you do is take a bale, wet it, fertilise it, wait for the
onset of cooling and them plant in it. The results are superb.


Regards to all  
                Ian Gill
                         Westland  New Zealand.
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