[Jimbo]

Hi,

Ive tried several times to grow brocoli, caulis, cabbage and brussels. Just about everytime they start their true leaves they collapse. They are in an unheated glasshouse (though I use a heater to stop temps going below 0 when needed)

Can anyone tell me what im doing wrong!!

Tks

[MacFistycuffs]

It sounds like it could be damping off, this is a fungus that affects seedlings. You can do a few things to ensure they do not fail.
1. Make sure the modules you starts the seeds in are clean.
2. Do not crowd the seedlings. Sow thinly.
3. Do not over water.
4. Covers the surface of the module or tray with perlite to keep the base of the stem dry.
5. Ensure that there is adequate air circulation in your greenhouse.

[michael brenock]

your seedlings are being wiped by damping off disease a non specific organism (can attack any type of plant). if temperatures are too low or vary too much day/night then this disease can occur. is worse in cold damp humid conditions and will spread very rapidly if seedlings are over crowded. Avoid watering overhead, reduce humidity and raise temperature. You might be sowing too early, sowing too thickly and over-watering.
Brassicas willl germinate at this time of year without artificial heat and frost should not be a problem in an unheated glasshouse from mid-march onwards.
You are still in time to resow.
michael brenock horticultural advisor (retired)

[Jimbo]

thanks for the help, I always clean the modules before use and do sow thinly, so ill try fix the other points!

cheers