Spring cabbage is delicious and tender and will be one of the first proper crops you can enjoy in the Spring. Remember Spring cabbage needs to be planted the previous Autumn to over winter and produce heads the following year.
Site and Soil
Spring Cabbage is classed as a heavy feeding plant so add plenty of garden compost and/or well rotted farmyard manure your soil before sowing or planting.
Cabbage takes up a lot of room in your garden needing up to 45-60 cm all round so the available space may dictate your numbers. Spring cabbages are smaller than Summer varieties, I would sow 14 cells and plant out the 10 best ones if you have the room. I highly recommend sowing your spring cabbage in modular trays. You can sow directly into the soil but I think you'll have better success with this method. Spring Cabbage is best sown in a greenhouse or similar environment between July and August for planting out about 4 weeks later.
Sowing in Modules
- 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.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.
Here's what you do:
- 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, polytunnel, cold frame or windowsill to germinate. They should be ready to plant out in about 4 weeks
Seeds can also be sown outdoors from mid early July. Sow 3 seeds 1.5 cm deep every 45cms. Thin out seedlings after 2-3 weeks to leave 1 plant every 75 cms. The spacing is 45 cm between plants and 45 cm between rows. Cover seed beds with fleece or enviromesh to protect against cabbage root fly at least until mid May when the risk will be reduced.
Seedlings grown indoors are at risk of becoming long and spindly or ‘leggy’. Leggy seedlings occur when the plant gets too much heat but not enough light. Seedlings growing early in the year can suffer because light levels aren't sufficient to balance the heat provided by growing indoors.
Growing on a windowsill - Always use a south facing windowsill with plenty of light. Place a mirror or other reflective material behind the plant tray to reflect daylight coming in the window on the dark side of the plant.
Using a heat mat, heating cable or propagator - As soon as the seedlings have germinated remove from the heat source. If growing in a greenhouse or tunnel protect the young seedlings at night by covering with horticultural fleece. Fleece will protect plants from temperatures as low as -3 degrees celcius.
Where 2 seeds have germinated in a single cell remove the weaker one by pinching out with your finger nail or cutting with a small scissors. Don’t pull them out to avoid damage to the neighbouring seedling.
Compost should be left moist rather than soaking. Avoid letting the seedlings dry to the point where the compost starts to pull away from the edge of the tray, it can be difficult to wet as the compost can form a crust on it’s surface.
Hardening off means getting your plants used to more hostile outdoor conditions. Leave the plants outdoors on mild days, progressing to every day and finally all night. A cloche cover or Cold Frame is perfect for this practice as the lid of the frame can be opened when warm and closed down in harsh weather and at night. 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.
Cabbages like a fertile, well-drained, moisture-retentive soil. A firm soil is also desirable so where possible add well rotted manure or garden compost in the Autumn and allow to settle over the Winter. Spring Cabbage should be planted 45 cm between plants and 45 cm between rows.
Water plants well before you begin. To plant a seedling make a hole in the soil about the size of the rootball with a dibber or trowel. Mix a slow release nitrogen rich feed like Seamungus poultry pellets around the planting hole and root zone.
Fill the planting hole with water several times before planting the seedling, this will help the plant to establish better. When planing 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.
You are better to transplant on a dull day or in the evening to prevent the plants wilting in hot, dry weather.
Pests and diseases
There are a number of brassica pests you need to look out for when planting Spring Cabbage. You can read more information about brassica pests and diseases here.
Cabbage root fly.
The best way to avoid cabbage root fly is to keep the flies out by covering your crops with a fine protection mesh like enviromesh. You must make sure the edges of the mesh are secure to prevent any intruders sneaking in by covering with soil or weighing down with bricks or stone.
Cabbage root flies lay their eggs around stems of seedlings where they hatch, burrow down and munch through the roots. You can also prevent this happening by placing cabbage collars around the base of the plants which the larvae can't get through.
You could also apply a natural nematode pest control which kills root fly maggots at the larval stage. A product like 'Supernemos' is excellent as it also attacks the larval stage of other pests like leatherjackets and wireworms.
Cabbage White Caterpillars.
Check periodically for small yellow eggs on the underside of the leaves and remove by brushing them off.
Cover the seedlings with fleece or micromesh to keep out cabbage white butterfly.
Remove any yellowing leaves at the base of the plant. Wash off whitefly with a strong jet of water.
More likely in established allotments or gardens than new or isolated gardens.
Clubroot likes acid conditions so adding lime (alkaline) to the soil before planting will help prevent the disease. Start your plants in modules. (I'd recommend that anyway) and grow in raised beds as clubroot likes wet conditions. To remove completely stop growing any brassica for at least 10 years.
Keep the soil clear of weeds using an oscillating hoe or similar. Hoeing is also beneficial as it invigorates the microbial life in the soil which makes more nutrients available to your plants.
Remove any yellow, discoloured leaves from the plant as they may harbour disease which will spread to your crop.
As Winter approaches earth up the cabbage stems by dragging soil up around the stems to prevent them rocking in the wind.
Pigeons can will be getting hungrier this time of year and may turn their attention to your brocolli. Netting is the only answer here and highly recommended if you have a pigeon problem. You will see sharp v-cuts in the edge of the leaves made by their beaks if this is your issue.
Remember 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. Weeds will be starting to build up again as the spring progresses so hoe regularily 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. Remove any yellow, discoloured leaves from the plant as they may harbour disease which will spread to your crop.
Thinning Spring Cabbage
You can remove every second cabbage as Spring greens in March and leave the remaining plants to heart up for harvesting in April/May.It’s a good idea to add a top dressing of ‘Seamungus’ poultry manure pellets or a liquid feed of organic seaweed plant feed at this stage. Add a handful of pellets scattered 45 cm around the stem.
Spring cabbage has a short harvesting period and need to be cut before they run to seed. Remember Spring Cabbage is a more conical shape than round Summer cabbages so they may be ready before you think they are.
Harvest cabbage by cutting the stem with a sharp knife close to soil level. Cut a deep cross in the remaining stump you will get a secondary crops of mini cabbages from the old stem.
Dig up the root after your secondary crop and preferably burn rather than compost to avoid encouraging club root.