July and August are ideal months to get a head start on weed control. Last Quarter phase is a good phase for weeding because seed germination tends to be lower then, and you are less likely to stimulate further weed seed germination while removing weeds. Many weeds that germinate in cultivated soil are and pests that damage vegetable crops. July is too late to eliminate the lawn weed Bindii as the spiky seed heads will be starting to form.
You can find organic treatments for troublesome weeds in the ‘Weeding Between the Lines’ category on this blog.
This is a good time of year to get a head start on weeding, as no-one likes weeding in hot weather. Leather gardening gloves or rigger’s gloves are great for weeding because they provide good protection from thorns, prickly stems, sharp edges of leaf blades, and insect or spider bites.
Weeds in the vegetable garden don’t just steal water and nutrients from your crops, many are also hosts to pests and/or diseases that can spread to your vegetables. By hosting diseases, weeds undermine your work at crop rotation to keep soil healthy.
Newly germinated weeds can be removed with a shuffle hoe, left on the bed surface, and covered with mulch. They will break down to return organic matter to topsoil. Small weeds that have not formed seed heads and are disease-free can be composted or put into worm farms. Larger weeds with seed heads must be removed and destroyed by burning, or soaking in water for an extended period, or disposed of in a sealed plastic bag. Remember the adage “One year’s seeds equals seven year’s weeds” – 15 years in some cases.
For gardening advice on removing troublesome perennial grasses and bulbous weeds, see my post on perennial weeds.
Nightshade (Solanum spp.)
The nightshade weeds are members of the same family as tomatoes, potatoes, capsicum and eggplant. Nightshade weeds (and Buffalo/Noogoora Burr) are hosts to Rhizoctonia fungi that can damage potato plants and tubers; cause collar rot in many plants, and cause damping-off in seedlings. They also provide a host to verticillium wilt that can affect a wide range of vegetables, fruit trees and ornamentals. Black Nightshade is a common weed in gardens. It grows to about 120 cm high, has groups of white (or purple-tinged) star-shaped flowers with a ring of 5 bright yellow stamens in the centre, and small green berries that blacken as they mature. Birds spread this weed by eating the berries.
Cobblers pegs (Bidens pilosa) This weed is also known in Australia as ‘farmer’s friends’ because the barbs at the end of seeds allow the masses of seeds to cling to clothing and animal fur. Each plant produces hundreds of seeds and this weed can grow into dense stands that can quickly fill an entire bed. It is a host for root knot nematodes, tomato spotted wilt, and sclerotinia rot that can affect many crop plants. Remove and destroy these weeds while they are very small.