Tender and out of season vegetables
Dutch lights, polythene tunnels or polythene mulch will be found of great assistance in raising out of season and frost tender vegetables.
Dutch light frames
Dutch lights consist of a single frame of 600g glass measuring 142 x 73 cm slipped into grooves on the long sides of a light wooden frame. These lights can be used to cover a frame with 60 cm back wall and 45 cm front wall. The frame may be heated by electric cables or crops may be grown without heat.
Polythene Tunnels
These are of two main types:-
- Low tunnels which have replaced cloches. A roll of 150 gauge polythene is supported by wire hoops and secured by twine. These tunnels are very useful for low growing crops or for providing shelter in the early stages of a crop’s development.
- Walk in tunnels – these are a low cost alternative to glasshouses. Polythene (600 gauge) is drawn tight over galvanised metal tubing forming a semicircular shape. These tunnels can be used for raising plants or growing more tender or out of season vegetables including tomatoes, cucumbers, melons, aubergines and sweet peppers.
Black Polythene mulches
If black polythene is laid on the ground and secured at the edges, many tender crops grow better than if planted into the open ground. The best system of culture is to raise the plants indoors or in a heated frame or glasshouse and to plant through holes in the polythene mulch when all danger of frost is gone. Tomatoes, gherkins, marrows and sweet corn benefit especially from these mulches.
Cropping Programmes
Under any of the above systems careful planning and management are needed if the protected area is to be utilised to full advantage. Suitable varieties should be used and dates of sowing and transplanting carefully studied. Many variations in cropping programmes can be employed. Early sowings of carrots in January will mature in May and can be followed by tomatoes, cucumbers, peppers or aubergines which in turn can be followed by lettuce. Alternatively lettuce can be succeeded by celery planted in late July for harvesting in early December.