Gareth Carter: Edible gardening in May

Now is a good time to prepare for strawberries. Photo / Getty Images

We are currently enjoying what has become a regular occurrence – a long lingering autumn with calm settled weather. Fine days with warm temperatures are contrasted by increasingly cooler nights. The cooling nights are a reminder that winter is getting nearer.

Moisture and warm temperatures are the key to good growth in the gardens for most plants. We are still enjoying numerous warm days and, as I write this, it is around 20C today.

These temperatures are so good for keeping growth going which is important for getting a good size on the brassicas in the vegetable garden before winter arrives and it pretty much grinds to a halt.

The unfortunate downside of the continuing warm weather is the proliferation of insect pests. After spraying my brassicas a few weeks ago and thinking that would be the last time for months, the population of whitefly and hungry caterpillars has increased, though I suspect by the number of holes I spotted that they are now not so hungry.

A spray with Yates Success or Mavrik will keep these in check and will ensure that I will get a harvest from my vegetable garden and not the caterpillars.

If you haven't made plantings of winter vegetables then do it now, for as winter draws closer, rain becomes more frequent and frost more likely and the garden becomes a much less inviting place than earlier in the year.

Making the most of fine days it is time for vacant ground to be dug over and fertiliser and or compost added to it. This is the best time to add lime to the soil in your vegetable garden. If you garden on heavy clay soil, the lime helps to combine with the very fine particles of clay soil to form into larger particles that are more easily cultivated.

It is the time to rake up all the leaves as they fall from trees and add them to your compost heap or make a specific pile of leaf mould. When composted this is excellent for use in planting and also helps the condition of the soil.

Note that leaves generally take longer to break down than other garden compost but a compost activator (Reln Garden Worm Farm & Compost Conditioner) is available to speed this process.

Materials suitable for composting include autumn leaves, grass clippings (unsprayed), hedge trimmings, straw, sawdust (untreated), wood ash (untreated), food scraps, vegetable peelings, tea leaves, leafy tree prunings, pine needles, sea weed, animal manure, egg shells and newspaper. Do not include animal fats, diseased plant material, oxalis or weed seed.

Broad beans are a cool season crop and it is time to start sowings of them now, with a second sowing in June or July as a successive crop. They are normally ready for eating in 16 weeks. They are best grown in full sun in well dug soil and sheltered from the wind. Protect from birds with bird netting - as the seeds germinate the birds tend to pull them out.

Place seeds in double rows 10-25cm apart and set the double rows about 90cm apart. This will help ensure that there is good pollination. Sow 5cm deep, cover with fine soil and keep moist. Water regularly as this is important during pod setting.

Pods picked at a young stage can be eaten whole although normally they are left to mature and only the beans are eaten. Broad beans like lime and sulphate of potash – apply to the ground before sowing. Check out the variety Mr Green Seed, part of a range of seeds called Chefs Best distributed by Ican.

Ican brand has been developed by a group of independent garden centres with the aim to put quality and value first, addressing the issue that we are in an age where price is often pushed lower at the compromise of quality. Garden experts have carried out extensive trials and sought advice from vegetable seed specialists nationally and internationally to find the very best varieties for the New Zealand home gardener.

You can sow a row or two of peas if you wish to grow your own. Peas like lime added to the soil. Soak the seeds for 4-6 hours to hasten germination. If sown now you should be picking them by October. The top variety that is part of the Chefs Best Ican range is Pea Magic; it has dark green pods on vigorous high yielding plants. Good resistance to fusarium and powdery mildew means you keep on picking till the last pod is produced.

If you haven't made plantings of winter vegetables then do it now

If you are keen to grow your own onions from seed, now is the time to be sowing sweet red, odourless and of course Pukekohe long keeper. The soil for all onions, shallots and garlic should be fertilised with potato food. When planting onions make sure the ground is thoroughly firmed.

If you do not intend to plant a winter vegetable garden, rather than letting the area become invaded with weeds, it is recommended that you sow a green crop. Growing a green crop is also good for flower beds and new garden sections. The most popular two are blue lupin and mustard.

Blue lupin is useful for the maintenance of soil fertility. It assists in recycling lost nutrients from your subsoil and adds a good level of nitrogen which is available to your next crops.

Mustard aids in the control of wire worm nematodes etc, which are problems often associated with root crops such as carrots and parsnips. Mustard also reduces the chances of any soil borne diseases within about 40 days of digging in. If clubroot is a problem don't plant brassica crops after mustard.

Brassica may need another treatment for the control of white butterfly caterpillar, whitefly and aphids which are common on brussels sprouts. Plantings of cabbage, cauliflower and broccoli can still be made.

Check brussels sprouts in your garden, particularly after strong wind, to make sure they are firmly in the ground and remove any yellow leaves.

This month is a good time to bring out any cloches you have. They are useful in the vegetable garden for warming the soil before sowing peas, onions etc. The warmer the soil at this time of year the better the seed germination. They are useful for covering lettuces and keeping off birds, and later on warming up the soil for early tomatoes.

Now is a good time to prepare for strawberries. Bareroot bundles of plants should be ordered in the garden centre now to ensure you don't miss out on getting plants at the best price. Strawberries would have to be the most popular berry fruit and a small patch in the home garden can provide a good supply over a long season. They tolerate a little shade but crop better and earlier in a sunny situation.

Brussels Sprouts

A practical idea is to plant strawberry plants under the clothes line where the flapping clothes will act to scare away birds. Avoid planting in areas which have been growing potatoes, tomatoes, peppers, aubergines or raspberries within the past three years, because strawberries can contract verticillium wilt and other root diseases from these crops.

Strawberry plants can be grown on a wide range of soils although medium to fairly heavy acid soils are best within a pH range of 5.8 to 6.2. Soils can be improved with the addition of compost or other organic material.

Good drainage is essential. Prepare the strawberry bed by digging in compost or manure several weeks before planting. Polythene or weed mat can be set down to suppress weeds, reduce disease risk and advance the crop. More about strawberries when they are available for planting later in the month.

Spray a good coating of copper spray onto any citrus trees that you may have to prevent brown rot on the fruit through the winter. I recommend Growsafe Freeflo Copper. It controls a range of fungal and bacterial diseases and in the form of a highly dispersible granule which mixes well when dissolved in water. It can also be mixed with Grosafe Enspray 99 which will control scale, thrips, mites and aphids which seem to be quite prevalent on citrus at the moment.

The presence of these bugs is often indicated by spreading black sooty mould which grows on the sugary excretion from some of these insects. Both these products are Bio Gro Organically Certified.

Under level 3 Covid-19 garden centres are currently closed for customer access. Shop online at www.springvalegardencentre.co.nz and choose from contactless pick up or local delivery options.

Have a great week!

•Gareth Carter is the general manager of Springvale Garden Centre