Tomatoes & Ring Culture


For reasons topographical (my plot slopes) I built my greenhouse above ground level with a wooden floor. This avoided the civil engineering to level the site but presented a problem – how do I grow my tomatoes? There are no beds to plant into and pots or grow bags are a pain to water (and to contain spillage) and are messy – answer ring culture.


Having some 25mm marine ply as an off cut from renovations to my kitchen, I constructed a box, somewhat reminiscent of a small coffin, about 1.8m x 60cm with sides about 30 cm high and a bottom, but no lid. The box was placed in the greenhouse taking up most of the long side, and then lined with two layers of clear polythene sheet. Into the lined box went clean pea shingle to a depth of about 15 cm. The bottoms were cut from five old 23 cm plastic pots with a craft knife and tomato plants carefully planted in JI No 3, leaving space for watering. Temporary polythene sheet bottoms were used to prevent the JI falling out.


The pots were placed on my shingle base and the temporary bottoms carefully removed. A good watering settled in the plants and supporting canes were attached to the roof of the greenhouse. This was the last water to be applied via the pots; future watering was into the shingle base, which was kept wet. When the fruit began to form the pots were fed with proprietary liquid fertiliser. All of this magic is possible because the plants form two distinct root systems, the water absorbing roots, which reach down into the shingle, and the feeding roots that form in the compost in the pots. A distinct advantage is the ease of maintenance as the water level in the base is not critical (unless it rises over the sides and causes a flood!). And the feeding just requires the dilute fertiliser to be added to fill the space at the top of the pots. It is all very clean and orderly and recyclable as the shingle in the base can be washed and reused each year.


The crops produced are the equal of those grown by more conventional means and the system seems capable of growing sweet peppers and other exotica – further trials next year.


By Bruce Jones

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