Gardening diary: Early autumn/fall

Gardening diary: Early autumn/fall

The cooler weather makes this the ideal time to sprout brassicas and winter root crops.

As March brings settled and cooler weather, you can say goodbye to the white butterfly. So it’s a good time to sprout your brassicas and winter root crops in anticipation of enjoying winter solstice fare from the garden.

These late season crops can be grown in all but those coolest regions of New Zealand which tend to have hard autumn and winter frosts.


To give the plants a head start at this time of year, buy seedlings of the following brassicas (cabbage family):

  • savoy cabbage
  • white cabbage
  • broccoli
  • Brussels sprouts
  • late season cauliflowers
  • kale

The soil, as ever, will need healthy application of well-rotted compost prior to planting out. Plant seedlings 60-70cm apart and give them a good watering immediately after planting (‘puddling in’). Cauliflowers will benefit from a handful of lime or wood ash sprinkled around the plant each month.

Apply a 15cm layer of untreated wood shavings or pea straw mulch over the ground (making sure it does not touch the stems of the seedlings) to moderate soil temperature and moisture content. Regular application of derris dust, or hand picking, will control any caterpillars.

Providing your soil is at least 60cm deep, there are also a number of root crops that can be raised from seed or seedlings, including:

  • carrots
  • parsnips
  • swedes
  • turnips

These like a finely crumbled soil with around 10 per cent sand or fine pumice added. Compost and mulch as for the brassicas. Don’t put fresh manure in the soil as it causes root crops to malform.

Maintain and harvest

If March is dry, then weekly deep watering will encourage full and healthy formation of tomatoes, capsicums, celery, lettuce, courgettes, squash, marrows, sweet corn, beans and eggplants — which should all be harvesting well.

Green waste from your vege plot can be added to the compost pile or worm farm — providing it looks healthy. If there’s any sign of disease, dispose of the waste off-site.

Gardening Q & A

Q: “Earlier in the summer, my courgette plants were doing really well but recently, a lot of the leaves have become covered in a white powdery film which rubs off when I rub my finger over it. I’ve looked for insects — none around. Is this something that needs treating?”

A Robinson, Hamilton

A: It sounds as if your plants have the fungal disease powdery mildew. Powdery mildew is more of an issue in summer when temperatures rise and the garden tends to be drier. Powdery mildew can infect many common garden vegetable varieties, in particular, pumpkin, beans and courgettes. It is not, however, limited to vegetables as it can also infect apple trees, grapevines and common garden flowers such as hydrangeas.

How to deal with powdery mildew

  • Remove the more severely affected leaves and dispose of them in the rubbish bin (preferably not the compost bin).
  • Regularly apply an organic sulphur spray to prevent the disease from becoming established.
  • Light watering of the leaves helps as powdery mildew does not like wet conditions. Be sure to water early in the day to allow the leaves to dry out to prevent other diseases becoming a problem.
  • Apply an organic oil which includes neem formulation as the oil smothers the fungal spores.
Author: David Haynes

Healthy Food Guide

First published: Mar 2012

2018-08-15 13:00:44

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