I have to admit when first learning some while back of the existence of Dobies grafted vegetable plants to being a little dubious. Not being a horticulturalist left me wondering what they were and why I should introduce them into our garden and greenhouse. What was (is) so special about grafting vegetables. Grafting as a technique has of course existed for ages – fruit growing springs particularly to mind where, for instance, a specific variety of pear, plum or apple is grafted onto a ‘wild’ and stronger rootstock.
Put simply, grafting is a technique whereby a shoot or twig is inserted into a slit on the trunk or stem of a living plant, receiving sap from the host until the two fuse and become one. Widely used by commercial growers, this technique of grafting top quality vegetables onto a more vigorous ‘rootstock’ has been shown to provide the following benefits: an increase in yield, more vigorous plants; earlier cropping and for longer; can be grown in the greenhouse (with little or no heating), or outdoors; an have an excellent resistance to soil borne diseases plus a greater tolerance to nutritional diseases.
Dobies (and their parent company, Suttons Seeds) are flying the flag: they are proud to be British by racing ahead of the rest in the gardening industry with vegetables which have been grown and grafted in the UK. And this year, the grafted tomatoes will use an improved grafting technique which will lead to even earlier and bigger crops, with fruit beginning lower on the stems and at least one extra truss per plant! Also available are grafted aubergines, peppers, squash, chillis, cucumbers and peppers.
Once you have your grafted plants, they should be potted on as soon as possible into 10cm (4″) pots using a good quality moist proprietary compost. Set the plants so that the top of the root ball is level with the compost surface. Once potted give a thorough watering but thereafter take care to avoid over watering. Grow on in a light, humid position at temperatures of approx 16-18°C (60-65°). After a couple of weeks when the roots have filled the pots, they are ready for planting in their final positions. The root systems of these plants have great vigour and should be given plenty of room if the plants are to achieve their full potential; a deep pot no smaller than 30cm (12″) is best for growing under glass. When planting always ensure that the graft union is kept above the soil level to prevent the scion rooting into the soil and reducing the plants resistance to soil borne
With tomatoes, the side shoots which appear at the leaf joints should be pinched out when they are about 2.5cm (1″) in length. Under greenhouse conditions grafted tomatoes are capable of setting and maturing six to eight trusses depending on the size of the fruits. Once the fruits start to set, a quality tomato fertilizer should be applied twice a week. The greenhouse should be lightly shaded to avoid exposure to strong sunlight and in hot sunny weather damp down the floor to increase humidity; great care should be taken to prevent the plants drying out, moderate regular watering being the best practice. down the floor to increase humidity.
Check the Dobies catalogue to read more about these heavier-cropping vegetables (pages 42-45). But due to the nature of these plants, no more will be available in 2012 – but make a note to check the 2013 catalogue when it becomes available. I meanwhile have been asked to trial a new grafted tomato variety not yet on the market; progress report in due course. Right now, the young plants are growing away strongly in the greenhouse.