Allotment Plot Holders' Guide:
Principles of Vegetable Growing
(part 3) Sowing/planting/after-care/protection/green manure.
Sowing, Planting and After care
If there are distinct beds and a formal crop rotation plan is to be followed, the preparation of the soil for each group of plants can be tailored to those plants.
|Lime the soil during winter if necessary. The pH should be 6.5-7. Rake in a general fertiliser 2 weeks before sowing or planting at the recommended rate||Rake in a general fertiliser 2 weeks before sowing or planting at the recommended rate||Add manure or compost when digging. Rake in a general fertiliser 2 weeks before sowing or planting at the recommended rate|
Suitable fertilisers include Blood, Fish and Bone @ 70 g/m² or Growmore @ 100 g/m².
Sowing and planting
Vegetables can be sown under cover, in a seedbed or in situ.
- Some vegetables, such as tomatoes or cucumbers, may be grown under cover for the whole of their life.
- Some may be started under cover because they are tender, such as runner beans, and cannot be planted out until the danger of frost has passed.
- Some may be started under cover to give them a longer growing season or to obtain an earlier crop.
In a seed bed
- A seedbed is used for the initial growth of plants while the space they will eventually occupy contains another crop.
- It also makes it easier to care for the plants during the critical part of their growth.
Plants are sown in situ where the seeds are large and easy to handle, such as peas and beans, or where they would not transplant easily, such as with root crops.
Planting for continuity
To derive the maximum benefit from the vegetable garden it is desirable to utilise all the space and have crops for harvesting all year round. Some techniques for achieving this are:
This is either:
- Sowing the same variety at intervals of time so that the whole crop does not reach maturity together.
- Sowing different varieties of the same crop. Many crops have early and late varieties.
This is the practice of growing a quick maturing crop in the space between slower growing pants, e.g. lettuce between brassicas, radishes between parsnips or spring onions between sweetcorn. The intercrop should not deprive the main crop of water or nutrients and it may be advisable to space the main crop a little further apart.
This is a quick maturing crop that is planted in an area that will be required later for a main crop. Plants suitable for intercropping are also suitable for catch crops. Green manures may be used as a catch crop to enrich the soil and keep it covered.
The following tasks may be required: watering, feeding, weed control, mulching, pest and disease control.
For vegetables the critical times for watering are:
- At the seeding stage
- At transplanting
- At flowering and during fruit development, when the vegetable is a fruit or seed, such as tomatoes, cucumbers, peas and beans
- At regular intervals for leafy and root vegetables
Seep hosed and automatic watering systems are particularly useful in the vegetable garden.
If organic matter and fertiliser are applied as part of the ground preparation it should not be necessary to feed any further, with the exception of nitrogen. Because some vegetables have a high requirement for nitrogen and it is easily lost by leaching, applying a top dressing or liquid feed during the growing season will be beneficial for leafy crops such as potatoes, brussel sprouts, cabbage, leeks beetroot and rhubarb.
Weed control is important on the vegetable plot, particularly among seedlings and young plants, as they compete for water, nutrients and light. Mulching, hoeing or hand weeding are the best methods of control. Use of chemical sprays is not recommended, as it is too easy to damage the vegetables. Spot treatment with a herbicide can be used for perennial weeds. If a chemical is used it should be one that is deactivated on contact with the soil, like Glyphosate.
Black polythene mulches of floating mulches are particularly useful in the vegetable garden. Floating mulches allow plants to be planted out earlier and will provide a degree of protection against pests and diseases. Loosely draped horticultural fleece can be used as floating mulch.
Pest and disease control
The following are some specific points relating to vegetable pests and diseases:
- Good hygiene is essential
- Crop rotation will help
- Physical protection may be needed against larger animals and birds
- Floating mulches may be effective against some insects.
Specific pests and diseases are covered in the details for particular vegetables.
Physical protection from pests
Protection may be required against birds or larger animals such as rabbits, cats or foxes. Some protection against birds can be provided by ‘buzz lines’. This is a form of tape that is stretched tightly across the plot and gives off a noise when moved by the wind. Growing all vegetables within a cage as is often done with fruit would provide better protection. The vegetables and fruit could be grown in the same cage.
Protection from rabbits, cats and foxes can only be achieved by some form of fencing. Rabbits are one of the worst pests in rural areas and the fence should be buried 15cm in the ground to prevent burrowing.
Green manuring is the technique of growing a crop, which is then dug into the soil. It has two advantages:
- It returns nutrients to the soil. Particularly the leguminous green manures.
- It protects the soil surface preventing soil capping, erosion and reduces the leaching of nutrients.
Green manures are sown in situ and dug into the soil before they flower. They can be cut and left to come again if required for longer and then dug into the soil. There are some that are suitable for over wintering and others that are only suitable for spring or summer sowings.
Green manures suitable for over wintering
- Essex red clover (Trifolium pratense) a leguminous plant that will enrich the soil with nitrogen
- Phacelia tanacetifolia – good for weed suppression.
Green manures suitable for spring and summer sowing
- Mustard (Sinapsis alba) – good quick source of nitrogen
- Phacelia tanacetifolia – good for weed suppression.
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