Hi, I have planted three punnets of cauliflower seedlings a month apart each and every single one went to seed as soon as the heads appeared. What causes this please? It seems to happen every year. I have had a lot of sheep pellets in my soil but I have also added general garden fertiliser and homemade compost as well. Thank you, Sandra.

Lots of things can cause “bolting”, some you can control, some you can’t as it is environmental. Bolting is where the plant thinks it is coming to the end of its life because of some sort of stress, so it needs to reproduce – it goes to seed.

Make sure the seedlings are fresh and new and haven’t been in the punnet for too long (don’t purchase them from the discount bin) as when you plant root bound seedlings they tend to go to seed. It can be the type of cauliflower seed used by the grower, look for a variety that is slow to bolt. Buy seedlings in single cell 6 packs rather than 6 seedlings in one punnet that need to be broken up to plant, this can cause transplant shock and lead to bolting.

Temperature fluctuations hot to cold to hot can cause plants to bolt. We have had a really mild autumn and almost a non-existent winter until the last few weeks. Make sure the varieties you are planting are the correct variety for the time of year, there are varieties that can tolerate heat and some that tolerate cold, most garden centres will have seasonally appropriate seedlings.

Apply Tui Organic Seaweed Plant Tonic to reduce transplant shock and help plants tolerate temperature fluctuations. You can apply this every couple of weeks at a rate of 30-70mls per 9L watering can.

Maintain regular even watering. Don’t let plants dry out and then give them a good soaking. Regular even watering is best, sheep pellets are good but make sure you don’t have too much nitrogen rich organic matter in the soil (compost, sheep pellets, chicken manure) as this will produce a lot of leaf and you need cauliflower to heart. Sulphate of Potash is good for hearting vegetables like broccoli, cauliflower and cabbage.

Read our Cauliflower Growing Guide >