Thanks to Jane at NZ Gardener, here are some top tomato tips to look after that much-cherished homegrown patch of veges over summer.
1. Provide shade and moisture. Tomato plants subjected to excessively hot, dry conditions will go into survival mode and shut down. The stomata (pores on the epidermis of the leaves) close up so that transpiration and respiration cease. Consequently the plant’s leaves will wilt. And without adequate water, blossom end rot may also occur. Once the period of heat stress is over, and enough water is supplied, the plant will return to rigidity and its leaves will function normally again. So in extreme heat, provide afternoon shade… and water, water, water!
2. Slap on a hat. Another consequence of extreme heat is sunburn. Where plants are subjected to too much heat and sunshine, without adequate water and foliage cover (which can occur when trimming off too many top laterals), fruit may burn, resulting in white or yellowy patches and sometimes blisters on the fruit. To prevent this, provide continuous moisture and some shading. Mulching will also help keep moisture in the soil for longer.
3. Give your tomatoes breathing space. Remove the lower leaves of your plants to allow more light, improve air circulation and deter disease. Keep the leaves higher up to protect fruit from the scorching sun.
4. Feed ’em. Feed plants weekly or fortnightly with a liquid fertiliser (Tom-A-Rite is ideal) or diluted manure tea to assist fruit production. Fresh manure or too much nitrogen fertiliser will encourage plants to produce leaves at the expense of flowers and fruit. Avoid fertilisers high in nitrogen just before and during cropping.
5. Watch for pests. Spider mite populations rapidly escalate in hot, dry weather. These pests suck the goodness out of your tomato plants and the leaves become dehydrated and turn a mottled yellow. Although small in size, an excess of mites results in the quick deterioration of plants. To control spider mites, use a miticide, a horticultural oil or insecticidal soap. Make sure you cover the entire leaf (especially the undersides) and follow up with another spray 10-14 days later. A follow-up spray is required to eliminate any larvae that have subsequently emerged from eggs.
6. Keep weeds at bay. Weeds compete for nutrients and often harbour pests.