Ring Culture

Ring culture is a specialized growing system which is best suited to tomatoes. The growing medium is free from pest and disease problems (as with plants grown in sterilized compost in a pot) yet allows roots to extend without any restriction.

Plants are grown in bottomless fibre cylinders filled with sterilized potting compost and roots grow into an inert medium which holds plenty of water and also provides stability. The system combines the advantages of growing plants in open border soil with those of growing in sterilized potting compost.

Begin preparations for ring culture by digging a trench to one spade’s depth. The soil can be removed from the greenhouse — it won’t be used. Line the trench with a single sheet of heavy-duty polythene. This will act as a watertight membrane and isolate the plant roots from the garden soil underneath (which may contain pests or disease organisms). Fill the trench with coarse washed gravel.

Transplant seedling tomatoes singly into 20cm (8in) fibre ring pots — or any suitably sized bottomless container — filled with a proprietary loam-based potting compost. Stand each container on the gravel bed, sinking them in to a depth of about 2.5cm (1in) to aid stability.

Fibrous feeding roots will eventually fill the container while anchorage and water-absorbing roots will grow into the gravel. Water plants via the gravel, but feed them by applying liquid tomato fertilizer to the compost in the container. Since the gravel bed has an open structure with plenty of air trapped in tiny pockets, the plant roots can be kept permanently moist without fear of waterlogging — tomatoes are quickly checked by periods of water shortage in normal all-soil growing systems in a greenhouse.