Hartley Magazine

All the latest news, hints, tips and advice from our experts

Planting potatoes and sowing biennials

If you’d like to eat new potatoes at Christmas (or earlier), it is time to plant them now, when late season, second early potatoes, stored in temperature-controlled conditions are sent out from late July to early August. They can easily be grown in pots. Stand two or three tubers on a 12.5cm layer of multipurpose compost in a 30m flower pot, then cover with a further 5-7.5cm of compost and water well. When the shoots are 15cm high almost cover them with another layer of compost, continue to do this until the shoots are within 5-7.5cm of the top of the container.  Move them into the greenhouse before the first frosts to stop the foliage from being damaged. Why not plant several pots? Some to be harvested earlier, others left for Christmas dinner. ‘Carlingford’ and ‘Charlotte’ are two varieties that are often offered. They can also be ‘chitted’ and planted from late August to early September.

Remove the lower leaves of tomato plants, so the sunlight ripens the fruit.

Make arrangements for someone to check on your greenhouse daily before going on holiday, showing your appreciation for their efforts by letting them harvest your crops. Regular harvesting ensures continuous cropping, so there should still be plenty left for you on your return. Write down the instructions concisely and go through them methodically to make sure that they are understood. Some plants may fail, unless you are lucky enough to have befriended a gardener but don’t be too harsh, as we know, you can replace the plant like-for-like or with something new and exciting.

Ventilate and shade when necessary. If temperatures are in danger of rising too high, use your greenhouse fan on ‘cool’ to circulate the air, or move containerised plants outdoors into shade.

Remove the lower leaves from tomatoes so the sunshine can reach the fruit, but don’t remove too many. Continue pinching out the tops of the main stems of tomatoes, once six trusses have formed or when they reach the top of the greenhouse. Keep harvesting crops like aubergines, cucumbers and tomatoes, chillis and sweet peppers so that the remaining fruits mature. Aubergines should be harvested while the skin is glossy, cucumbers once they have reached 12” long and chillies and sweet peppers when the whole fruit has coloured.

Continue sowing ‘cut and come again’ crops in pots, like mixed herbs; mixed salads can be started under the greenhouse benching then moved outdoors. Sow chicory and chard for leaves, chervil, coriander, parsley and rocket, lettuce, salad onion, spinach and spring cabbage for crops later in the year.

If you have had problems in the past with vine weevil, now is the time to drench plants like cyclamen with the biological control nematodes. They work better in lighter composts like peat free multipurpose.  You can also buy traps containing nematodes, or use sticky traps as control.

If you haven’t done so already, sow Foxgloves, Hollyhocks, Canterbury bells, and Delphiniums in trays of peat free compost a cool greenhouse for planting out and overwintering in October, for flowering next year. Sow them in cold frames or outdoors further south.

Happy gardening. Matt.