The mercury is dropping and gardeners around the country will be moving tender pot plants back into the comparative warmth of the greenhouse. Whilst this is undoubtedly good news for the plants in question, they may be harbouring nasty pests that will move on to attack everything else around them.
The prime suspects in this potential crime scene are slugs and vine weevils. You most probably will have no idea whether they are lurking sub-soil in the pots and containers. But once they begin to warm up, they will quickly become active and start looking for new lunch hosts.
Linda Lane, the managing director of Griffin Glasshouses, believes that a more natural approach to resolving the pest issue is best and she uses nematodes in her greenhouse. These microscopic worm-like creatures occur naturally in garden soil where different species attack very specific prey. Proprietary nematode treatments are mixed with water and delivered to the pots and containers via a watering can with a coarse rose.
“A couple of treatments in October should kill them off and prevent causing mayhem in the winter greenhouse. They are a natural and environmentally safe solution to pest control. The slug and vine weevil killer use two different nematode species but they can be mixed together to create a total control,” she explains.
“They cause absolutely no harm to non-target species so other natural pest controlling insects that will live in the warm greenhouse are not at risk.”
Linda’s other advice for getting the greenhouse ready for the cold weather includes:
- Cleaning the glass on the inside and out to maximise the heat from any winter sun;
- Keeping the greenhouse clean and healthy and washing down surfaces with a mild disinfectant;
- Don’t use the greenhouse as a storage area for pots, seed trays and half used bags of compost. These are potential havens for other pests to over winter;
- Make sure greenhouse heaters are working properly and that you have sufficient fuel;
- Keep doors and windows open during warmer weather as air circulation will help prevent disease;
- Tomato, aubergine and peppers are among the plants that will still be fruiting but slow down on the watering. As the power of the sun reduces so does the condensation of excess water and the excess can cause mildew and rot. Remove the plants and their supports once they have finished fruiting;
- Cut back vines once any grapes have been harvested and check that they remain securely tied up.
“The greenhouse is brilliant for extending the growing season and lettuce plants can still be grown in protected areas. It is vitally important to keep all areas clean and healthy,” says Linda.
Nematode pest control products can be purchased online from The Green Gardener.