Warm and wet bad for the garden
Summer sunshine may be bliss for the average person but a bout of warm, wet weather spells trouble for vege gardens. Humidity encourages fungal diseases and, in their weakened state, infected plants are susceptible to bacteria and viruses as well. Watch out for late blight on tomatoes and potatoes, especially if there is a drop in temperature at night. Late blight thrives in humid conditions where nights are cool and days are warm. Tell-tale signs of infection include brown-black spots on leaves and sometimes a white fungal growth on their undersides. Leaves eventually shrivel up and fall off. The disease can also spread to potato tubers, which eventually rot. You can spray with Kiwicare’s Organic Copper Oxy, which protects plants from both fungal and bacterial diseases, though the best course of action is to try to prevent the disease from infecting plants in the first place. Avoid planting potatoes and tomatoes in the same spot each year, as the disease can remain in the soil. In autumn, gather and dispose of all fallen leaves and fruit to reduce the chance of the disease overwintering. At the end of the season, dig out all potato tubers as well. Any that remain may also harbour the disease. Powdery mildew also rears its ugly head at this time of year. Spray regularly with your own DIY fungicides – a milk spray or baking soda spray. It is suggested that organic raw milk works best as it still contains the natural antibiotics that may otherwise be destroyed during pasteurisation. The natural antibiotics in milk, as well as the production of other constituents upon exposure to sunlight, act as a natural fungicide. However, many gardeners believe skim milk is as equally effective in controlling powdery mildew. In either case, use one part milk to nine parts water and spray every 7 to 10 days. For a baking soda spray, mix 1 tablespoon of baking soda with a litre of water, add a squirt of detergent for stickability, and spray on to leaves. Rust is another disease that’s prevalent in summer. You often see it on asparagus, mint, beans, beetroot and peas (including snow peas and sugar snaps). It shows up as rustcoloured spots on leaves. Remove infected leaves as the spores are easily released into the air and blown on the wind to infect other plants. They may also fall on to the soil surface and overwinter there. It is best to remove infected plants and start again with new plants in a different spot. Healthy plants can be sprayed with a copper fungicide to prevent infection. Rust may be encouraged by too much nitrogen and too little potassium in the soil. Use a balanced fertiliser, one with at least as much potassium as nitrogen, on rust-prone crops. A seaweed fertiliser supplies potassium, as well as trace minerals plants enjoy.
Watch out: Tomatoes and potatoes are vulnerable to blight
at this time of year.