Care and Cultivation of Greenhouse Vegetable Collection
What to do
Sending plants by post may cause them a little stress, so unpack them immediately and, if dry, stand them for a few minutes in about 2.5cm (1in) of water, until the compost is fully moist again. You may notice a slight yellowing of the foliage or that they look a little drawn but this is quite natural after they have been in a dark box and is nothing to be worried about, they will soon recover. Now stand them in a bright, airy position, out of direct sunlight and where there is gentle warmth. Having been carefully nurtured under ideal glasshouse conditions, your plants will be sensitive to both cold and scorching sunshine. Suitable places would be a conservatory, greenhouse or bright windowsill, where a minimum temperature of not less than 13˚C (55˚F), or 15˚C (60˚F) for cucumbers, can be maintained.
Growing Them On
Your plants have arrived ready for transplanting and should be potted on as soon as possible. If you find a fine mesh around the plugs, there is no need to remove this before potting as the roots can easily grow through it into the surrounding compost. Pot them first into 10cm (4in) pots. Use any good multi-purpose compost and set each one so that the top of the plug is just below the surface. Tap the pot to settle the compost but do not over-firm. As soon as you have potted your plants, water them in well. After that, wait until the surface of the compost starts to dry before watering again. Your plants are unlikely to thrive if over-watered. If you have to grow on your plants in a place where they only receive light from one side, such as on a windowsill, turn them regularly so that they grow evenly.
After about three weeks, when they are well grown and their root systems have filled the pots, all varieties will be ready for planting out in a greenhouse, conservatory or polytunnel. This should be about the middle of May and, at this stage, tomatoes should be 15-20cm (6-8in) tall, with the first flowers just starting to open. Tomatoes, aubergines and peppers can be planted directly, 45cm (18in) apart, into a greenhouse border but most people prefer to plant them individually in 22cm (9in) pots filled with multi-purpose compost, or to use gro-bags, each of which will take three plants. To avoid a build-up of pests and diseases, it is best to avoid using greenhouse borders if they have grown these types of plants for two or more years previously, unless the soil can be sterilised or changed. Cucumbers should be planted two to a gro-bag or singly in 25cm (10in) pots.
Ideally your greenhouse should have sufficient heating to maintain a minimum of at least 13˚C (55˚F), 15˚C (60˚F) for cucumbers, in the first 2-3 weeks after planting out, should it still be needed. Failing this, be prepared to either move your plants to a warmer location (if potted and still small) or to wrap them with at least two layers of fleece on any cold nights. All varieties may suffer injury if exposed to excessively low temperatures and will be killed if frost gets into your greenhouse. Cucumbers are particularly vulnerable. Water regularly to keep the soil or compost moist at all times. In warm weather, plants in gro-bags and pots will need watering daily. Irregular watering can lead to problems such as blossom-end rot of tomatoes and peppers. Most gro-bags and commercial composts contain enough fertiliser to support plants for the first few weeks but, once fruits start to set, add a high potash, tomato-type fertiliser to the water at manufacturers recommended rates. All varieties in your collection will require some support and training as they grow:
• Tomatoes should be restricted to a single stem. Tie them loosely to a strong cane at regular intervals or, in a greenhouse, they can be wound around a securely anchored vertical string as they grow. Pinch out all side shoots as they appear and remove the tips of the plants when they reach the top of the greenhouse.
• The main stems of cucumber plants should be similarly trained up vertical canes or wires and have the tips removed when they reach the top of the roof. In this case don’t remove the side shoots but, instead, pinch out their tips at two leaves beyond a female flower.
• Peppers and aubergines normally also require the support of a cane as they grow and the tips of aubergines should be pinched out when they are about 30cm (1ft) tall, to encourage them to bush out. As aubergine fruits are large and heavy, it is best not to allow more than two to develop on each branch. Shade glass during the summer months and ventilate above 20˚C (70˚F). ‘Damping down’ the floor of the greenhouse on hot days to raise air humidity is very beneficial, particularly for cucumbers. Regular misting will help fruit set of tomatoes, peppers and aubergines. Gently shaking or tapping tomato trusses will also help disperse the pollen.