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How To Grow Cauliflower

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How To Grow Cauliflower

How To Grow Cauliflower

Fresh heads of homegrown cauliflowerThe cauliflower is not the easiest of the brassica family to grow but a large white cauliflower with tight white curds is a thing of beauty and producing one a source of much satisfaction. Variety is important, especially for beginners with a very healthy and well fed soil essential.

Cauliflower likes cool growing conditions and quite high humidity. They need a deep rich soil and must be kept well watered throughout the season. Any check in their growing cycle will result in tiny heads and a frustrated gardener! In short they tricky.

You can sow Cauliflower in late March, early May and early June for a long cropping season. I highly recommend sowing your cauliflower in modular trays. You can sow directly into the soil but I think you'll have better success with this method for the following reasons:

  • Excellent crop establishment
  • Uniform plant development
  • Quick transplanting with minimum root disturbance
  • Gives the plant a head start against weather and garden pests and diseases.

Sowing seeds in modular traysSowing in Modular trays.
Use a seed compost which has a finer texture and lower nutrients than your standard multipurpose compost. We use a seed module tray with each section being approx 2 inches deep.

Fill the seed tray with compost and brush off any excess. When filling the tray rub the compost through your hands to break up any lumps. Give the tray a sharp bang on your table to settle.

With your fingers make small depressions in each cell about a fingernail or 1.5cm deep. Sow 1 or 2 seeds per module. If 2 seeds germinate you will have to remove the weaker seedling.

Cover the seeds with another layer of compost then scrape across the top of the tray with a stick to remove excess. Gently water your seeds. A good tip is to use a plastic bottle with small holes punched in the cap. This is less likely to wash the seed around than the heavy spray from a watering can. Place your trays in your greenhouse, poly tunnel, cold frame or windowsill to germinate. They should be ready to plant out in about 4 weeks. If you're sowing in March the seeds will need some warmth. Use a propagator, heat mat or a warm south facing windowsill.

Seedling Care

tall and spindly leggy vegetable seedling plantWhen growing seedlings indoors you be careful they don't get leggy, i.e. long spindly plants.

Seedlings become 'leggy' when they get too much heat and not enough light. If you are starting them off on a windowsill make sure they get as much daylight as possible. You can make a makeshift light box by placing a sheet of reflective tinfoil on the room side of the seedling tray. This will reflect daylight onto the darker side of the plant.

If the plants are on a heat bench or in a propagator and they are looking spindly, turn the heat down and try to give them as much light as possible. If 2 cauliflower seedlings have germinated in any of your modules you need to remove the weaker one. Don't pull the seedling out as you'll damage the roots of the one you want to keep. Nip the unlucky one with your finger nail or cut with a scissors.

 

New vegetable seedling plants need gentle wateringWatering.
It's important to keep you seedlings properly watered before you plant them out in the garden. You are actually far better to under rather than over water your plants. This may sound odd but making the roots search for water helps to develop a better root system. It's a bit like keeping fit.

You do need to be careful, however, not to let the compost plug completely dry out or it will form a crust on top and won't absorb the moisture the next time you water. It will all depend on the weather of course but on a hot day you will need to water twice a day, if it's it's dull every 2 days will be fine.

Hardening Off

Timber framed cold frame for hardening off plantsPlants that have been raised indoors will need to get used to the outdoor temperature and conditions before they can be planted outside, this will take about a week to 10 days depending on the weather.

The best way is to use a cloche or mini greenhouse. You can leave the cloche off the plants on dry frost free days and replace at night. Gradually increase the time with the cloche removed until the end of the week when you leave it off day and night. If the weather is mild you may not need the cloche, just move the plants outside for longer periods each day.

If you have started your seeds on a windowsill you will need to leave them in an unheated room for a day or two before moving outside to the cloche.

Planting Out

Planting cauliflower vegetable seedlingsCauliflower plants should be planted 60cm between plants and 60cm between rows. The distance between the plants will determine the size of the head so try to stick to the recommended distance. The closer you plant, the smaller the head.
It has become fashionable recently to grow mini cauliflower so if you want to keep up with the Jones's you could plant 15cm x 25cm.

Like cabbage, cauliflower needs a well compacted soil so ideally have your digging and manureing done a couple of months in advance. If this isn't possible make sure you firm around the seedling very well with your boot, it's o.k. to be heavy handed here as firm soil is very important.

Water your plants well an hour before planting. To plant your seedling make a hole in the soil the approximate size of the seedling 'plug'. You need to push the soil in around the roots firmly with your fingers to get good contact with the soil. Don't firm down on the top of the soil as this can compact it and prevent moisture getting down to the plants roots.

Water the plants after planting but do not soak them. You are better to transplant on a dull day or in the evening to prevent the plants wilting on a hot, dry day.

Pest and Disease Control.
I don't want to put you off but there are a couple of things you'll need to look out for when you've planted your seedlings. Cauliflower belongs to the cabbage or Brassica family so all the same pests and diseases apply as cabbage, Cabbage root fly, Cabbage White Caterpillars, Cabbage Whitefly, and Clubroot.

Cabbage root fly maggotsCabbage root fly
Cabbage root fly is a small grey fly a bit like a small house fly. It lays it's eggs at the base of cabbage seedlings, the eggs hatch into maggots and then burrow down to feast on the new roots of your plants.

Symptoms:
Young plants will begin to wilt and eventually stop growing. The leaves will start to take on a blue\green colour. If you bite the bullet and pull up the plant you will see white maggots tucking into the roots.

Control:
The best organic method of control is to cover your calabrese with bionet (micromesh) to stop the fly laying it's eggs. Make sure the net is sealed all the way round to prevent access by the fly.

Cabbage collars. You can either buy or make these yourself from roofing felt or carpet underlay.
The collars are a circle of material covering the soil around the base of the plant which helps prevent the root fly laying its eggs around the stem and stops the maggots burrowing down to the roots.

Nematodes. These are naturally occuring microscopic worm which attacks the larvae of the cabbage root fly. The nematodes are in your garden soil anyway you're just increasing the numbers. It is a non chemical product so is safe for use around pets and children. You will need to do a couple of applications but in my opinion it's well worth it as you'll also protect a whole host of other crops.

 Cabbage White Caterpillars.
The caterpillars of the cabbage white butterfly will reduce your plants to a skeleton within a couple of days so clearly it's best to keep on top of them. Look out for the yellow eggs of the butterfly under the leaves and brush them off. It's much easier to remove the eggs than the caterpillars so this is well worth doing. The caterpillars in the photo are babies, they'll get a lot bigger and do a lot more damage if you let them!
The best and easiest method however is to cover your crop with bionet as with root fly.

Cabbage Whitefly
The Cabbage whitefly is an aphid (Like a greenfly, except white), it is less troublesome than other cabbage pests but worth keeping an eye on. The adults are tiny white insects which you'll find on the underside of the leaves. They produce a sticky substance called 'honeydew' which will probably cause a grey mould later.

Remove any yellowing leaves at the base of the plant as they may be harbouring aphid eggs. You can wash off whitefly, honeydew and grey mould with a strong jet of water.
 
Club root cauliflower plantClubroot
Clubroot is one of the most tricky diseases you'll encounter in the garden but with proper precautions it can be successfully controlled. If you start a new vegetable garden the chances of having clubroot are pretty slim and you can prevent it entering quite easily. If you do get clubroot the cysts survive for up to 9 years in the soil. You won't be able to grow any of the cabbage family (Brassicas) until it's gone so you've been warned!

The disease usually arrives in your garden through infected transplants or by walking from infected soil into a virgin patch. If you have an isolated garden you are unlikely to get it whereas you need to be more careful in established allotments.

Symptoms:
Poor growth with wilting leaves of a reddish-purple colour. If you pull up the roots you'll see swollen, knobbly deformed growth with a pungent foul odour. In more advanced cases the roots will have dissolved into a slimy pulp.

Prevention:
If you have clubroot already seek out varieties with resistance to the disease, this will be clearly marked as an advantage on the pack. Otherwise you'll just have to live with it, you can minimise it's effects by doing the following:

  • Not composting your brassica roots, burn them.
  • Don't sow brassica famiy green manure. (Mustard, Rape)
  • Start your plants in modules. (I'd recommend that anyway).
  • Lime the soil the previous Autumn to make it more alkaline (Clubroot likes acid conditions).
  • Grow in raised beds as clubroot likes wet conditions.

Crop Care

Cabbage white butterfly yeloow eggsRemember to keep an eye out for cabbage white butterfly eggs on your cabbage plants. Look under the leaves for the little yellow eggs and brush them off.
It is much easier to cover your crops with micro mesh (enviromesh) if you haven't done so already. Make sure no butterfly gets in while you're doing it!

Watering
Cauliflower must never be short of water, especially in the early stages or very small heads will form which won't get any bigger. Research has also shown that if the soil is kept moist at all times the yield will be greatly increased.

Feeding
Cauliflower is also a hungry crop so apply a feed every 4 weeks or so. Our 'Seamungus' seaweed-chicken manure pellets are an excellent source of nitrogen which will be perfect for leafy crops like cauliflower. If you want to give the plant a quick boost a liquid seaweed feed is ideal.

Oscillating stirrup hoe best weeding toolHoe regularly to control weeds and to stimulate the growth of the plant. One of the best gardening tools you'll ever buy is the oscillating stirrup hoe. It's a very effective old fashioned tool that really works properly.
Hoeing not only removes the weeds but it also breaks up the surface of the soil and creates a fine texture or 'tilth'. A good tilth lets air and moisture in to the roots of your plants thus increasing their vigour.
 

Remove any yellow, dis-coloured leaves from the plant as they may harbour disease which will spread to your crop.

Harvesting Cauliflower

Cauliflower nHarvesting a couliflower head with knifeeeds to be harvested on time otherwise the curds (White heads) will turn brown and rot. What a shame considering all the work you've put in!

If you planted a number of cauliflower it's best to start harvesting some of the small ones while you're waiting for the rest to mature. This is because they will all be ready at the same time and don't store well. It the florets begin to separate then you've waited too long.

Cut the cauliflower head at the base of the plant. It's a good idea to keep the leaf wrapping intact to prevent the curd from damage. The best time to pick is in the early morning when there's still dew on the plant, if it's frosty you're better off waiting till midday.

If you wish to store the cauliflower for 2 or 3 weeks lift the whole plant including the roots, shake off any excess soil and hang upside down in a cool shed. Spray the head occasionally with water to prevent drying out.

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