Topic: Hardening Off

[tim]

A little spiel on this vexed subject might not go amiss??

Yes, basic theory is fine, but when you have only one frame - or even two -  and a succession of plants at different stages to deal with, I find the whole thing a bit of a lottery. = Tim

[The gardener]

I agree Tim,

I think cold frame space is more important than heated space, simply because heated space is only required for a relatively short period where hardening off can take some time.

I have taken the liberty of explaining my method by copying my set up details from my website. (see below)

As you can see I have three areas of heat in my heated greenhouse and also have my cold frame at home.

The cold greenhouses are on the allotment.

There is a picture of my heating layout on the propagation pages of my website.

My set up

   * I have one heated 10’x8’ (3mx2.4m). Three unheated greenhouses one is 28’x8’(9mx2.4m) one 12’x8’ (3.6mx2.4m) and 8’x6’ (2.4mx1.8m plus an 8’x3’(2.4mx0.9m) cold frame

The 10’x8’ greenhouse is used primarily as a propagating area and a place to store plants requiring frost protection during the winter.

The other three and the cold frame are used as ‘hardening off’ areas in the spring and for growing subjects that require protection during the rest of the year.

10’x8’ Greenhouse

   * Insulation; In winter I insulate the outside rather than the inside, I find this method of insulating keeps my greenhouse much dryer i.e. less condensation forms and gives me more space. It also easier to fix in place otherwise I would have to remove and refit the shelving.

   * Heating; For economic reasons I have three forms of heat concentrated at various levels rather a general temperature throughout the greenhouse they are as follows;

   * General heating;

When I require ‘frost free’ conditions I run a thermostatically controlled fan heater at around 35-40F(3-5C).

When I start up my seed and cutting programme in January/February I raise the fan heater temperature to maintain a general temperature of around 50F(10C).

   * Bottom heat;

I have a thermostatically controlled heated bench for rooting cuttings or germinating seed that require a temperature of between 50/60F (10/15C).

The 7’x 2.6’(2.1m x 0.75m) hot bed is a box formed with tanalised timber and lined with 1”(25mm) thick polystyrene sheets filled with river sand.

In the sand, is placed an 80’(24m) 300watt soil warming cable controlled by a ‘Rodstat’

   * High level heating;

When temperatures of 65F(15C) and above are required, I use a purpose made thermostatically controlled propagator (575m x 290mm), which I manually adjust to the desired temperature.

   *  Lighting;

I use a time controlled fluorescent light above the hotbed to supplement the poor natural light of the winter months, thus speeding up growing/rooting times.

   * Storage;

The bottom shelves of my benches have been constructed at a height suited to getting bags of compost to go under.

   * The three cold greenhouses are generally empty over the winter months and are first used when hardening off plants prior to planting out the less hardy fruit and vegetables.

The cold frame it is in use all the year round.

   * If I were asked what item is of most benefit to the gardener then I would have to say the cold frame.

Every garden should have at least one, even if it is of the flat pack variety and is erected / dismantled as required to save space, it is a must.

[cleo]

There is mythos and logos-for me the notion of `hardening off` is much overdone.

Yes maybe toms and aubies etc may need some accommodation before the rigour of outdoors but the years have suggested that the `lore` on this question is not based on facts.

Having said that I would be the last person to suggest that frames are not the one of the most useful things one can own after a spade and fork.

Stephan

[tim]

- or an irresistible urge to interfere with nature!!

As to h/o - was hoping someone would say that. = Tim

[Mrs Ava]

hmmm...I always have such good intentions, and I do start, but suddenly I am overwhelmed with plants and trays of seedlings and I just run out of time, or patience!  I heat my greenhouse only when there is frost forecast.  It is insualted with good old bubble wrap, and it is very sheltered, and even when we have had a surpise frost, my most tender plants have been fine.  Therefore.....I kinda feel things are hardish anyway, as they haven't been forced with lots of heat.  

[campanula]

i do not heat anything - they either grow or die - and they grow tough!

[tim]

I hasten to add that we do not force anything. Encourage, I think, is the word?

We give enough warmth to germinate the peppers, cus, toms etc, and continue with just enough to develop a strong root formation.

There's certainly no point in pushing things on beyond the light available. And since all our propagation is done in a lean-to, things tend to lean very quickly without it.

Would love to go back to artificial lighting - that really was exciting. Lettuces in the kitchen??  = Tim