August New Zealand Gardening Calendar
August marks the transition from winter to spring across New Zealand. While frosts are still common in many areas, the days are becoming noticeably longer and the first signs of spring are beginning to appear. Daffodils and other spring bulbs brighten gardens, fruit trees are preparing to burst into growth, and gardeners can finally look forward to the busiest and most rewarding season of the year.
This is one of the most important months on the gardening calendar. Jobs completed now will help ensure healthier plants, stronger growth and better harvests throughout spring and summer. It’s the ideal time to finish winter pruning, prepare vegetable beds, plant trees and shrubs, and sow the first hardy vegetables. Taking advantage of fine weather during August will put you well ahead before spring growth begins in earnest.
Whether you’re growing vegetables, fruit trees, flowers or simply maintaining your home garden, this August New Zealand Gardening Calendar will help you make the most of the month.
August Gardening at a Glance
- Finish winter pruning before new growth begins.
- Plant deciduous trees and shrubs while they are still dormant.
- Prepare vegetable gardens with compost and lime if required.
- Begin sowing hardy vegetables for spring harvests.
- Plant asparagus crowns, potatoes and rhubarb.
- Prune kiwifruit, berry fruit and feijoas.
- Keep weeds, slugs and snails under control.
- Turn compost heaps and prepare new ones.
- Take advantage of every fine day to get ahead before spring.
General Gardening Tasks for August
August signals the beginning of the busiest gardening season of the year. Although winter hasn’t completely disappeared, gardens quickly come back to life as temperatures slowly increase and daylight hours lengthen.
Use every spell of fine weather to work outdoors. Finish any outstanding winter jobs, tidy garden beds, repair fences and edging, clean tools and prepare your garden for the rapid growth that spring brings. If you’re planning new gardens or landscaping projects, now is the time to finalise your plans and gather the plants and materials you’ll need.
Keep an eye on weather forecasts, particularly in colder regions where frosts can still damage tender new growth.
Regional Gardening Advice
Warmer Areas
Gardeners in Northland, Auckland, Bay of Plenty and other mild coastal districts can generally begin planting and sowing a little earlier than the rest of the country. Growth is often well underway by the end of August, so it’s worth taking advantage of the warmer soil temperatures.
Colder Areas
Gardeners in inland districts and much of the South Island should continue to expect frosts. Delay planting frost-sensitive crops outdoors and consider starting seeds under cover, in greenhouses or indoors until conditions improve.
Pruning
Finish all winter pruning as early in August as possible before trees and shrubs begin producing vigorous spring growth. Pruning while plants are still dormant encourages healthy new shoots and helps shape plants for the coming season.
Remove any dead, diseased or damaged branches and improve airflow by thinning overcrowded growth. Always use clean, sharp secateurs or pruning saws to minimise the risk of spreading diseases.
Dispose of diseased prunings away from your property rather than composting them, particularly those affected by fungal diseases such as silver leaf.
Planting
August is an excellent time to plant most deciduous trees and shrubs before spring growth begins. Plants established now usually develop stronger root systems before the warmer, drier weather arrives.
If you’re planning to plant deciduous ornamental or fruit trees, don’t leave it too long. Popular varieties often sell out quickly as spring approaches. While late winter sales sometimes offer discounted trees, these are often the remaining nursery stock, so select healthy plants with well-developed root systems.
When planting, enrich the soil with compost, water thoroughly after planting, and apply a layer of mulch to conserve moisture and suppress weeds. Keep mulch away from the trunk to reduce the risk of rot.
August New Zealand Gardening Calendar for Vegetables
Late winter is the perfect time to prepare vegetable gardens for the busy growing season ahead. Remove old crops, pull out weeds and clear away any diseased plant material to reduce pest and disease problems later in spring.
Spread a generous layer of compost over garden beds to improve soil structure and fertility. If you prefer cultivating your soil, dig the compost in while conditions are suitable. Heavy clay soils are best left until they’re moist but not waterlogged.
Check Your Soil pH
August is also a good time to test your vegetable garden’s soil pH. Most vegetables grow best in slightly acidic to neutral soil with a pH of around 6.5. Over time, many New Zealand soils naturally become more acidic, so applying garden lime may be beneficial if your soil test indicates it’s needed.
Simple soil testing kits are available from most garden centres and provide a quick indication of your soil’s condition.
Sow Vegetables
Make successive sowings every two to four weeks rather than planting everything at once. This helps spread your harvest over a longer period and avoids large gluts of produce.
Warm Districts
- Cabbage
- Celery
- Lettuce
- Onions
- Spring onions
- Silver beet
- Spinach
- Carrots
- Parsnips
- Beetroot
- Peas
- Radishes
Colder Districts
- Broad beans
- Peas
- Parsnips
- Swedes
- Turnips
In colder parts of New Zealand, many seeds will germinate more reliably if started in trays under cover or in a greenhouse. Bottom heat can improve germination for some crops where temperatures remain low.
Plant During August
- Asparagus crowns – Plant into well-prepared, free-draining soil for many years of productive harvests.
- Early potatoes – Chit seed potatoes by placing them in a bright, frost-free location for seven to ten days before planting to encourage strong shoots.
- Rhubarb – Plant crowns, divide established clumps or grow from seed if preferred.
- Tomatoes – In warm districts or heated greenhouses, tomatoes can be planted now for an early crop.
Herb Garden
Many hardy herbs can be sown or planted during August, particularly in warmer districts. Fresh herbs are easy to grow and provide a rewarding harvest throughout spring and summer.
Suitable herbs include:
- Parsley
- Rocket
- Dill
In colder districts, sow herbs under cover until the risk of severe frosts has passed. Well-drained soil and plenty of sunlight will encourage healthy, vigorous growth.
August New Zealand Gardening Calendar for Fruit Trees
August is one of the most important months for caring for fruit trees in New Zealand. With spring only weeks away, now is the time to complete pruning, carry out preventative disease control, and finish planting new trees while they are still dormant.
Pip and Stone Fruit
Complete pruning of apples, pears, peaches, nectarines, plums, apricots and cherries before buds begin to swell. Winter pruning encourages strong new growth, improves air circulation through the canopy and helps produce healthier fruit later in the season.
Remove any dead, damaged or crossing branches and open up the centre of the tree where appropriate. Good airflow helps reduce fungal diseases and allows sunlight to reach developing fruit.
Dispose of prunings away from your garden if they show signs of disease. Fungal diseases such as silver leaf can survive on infected wood and spread to healthy trees if left nearby.
After pruning, apply a winter fungicide spray such as copper oxychloride or Bordeaux mixture according to the manufacturer’s directions. A dormant spray can help reduce fungal spores before spring growth begins.
Grafting Fruit Trees
August is the ideal time to collect scion wood for spring grafting. Select healthy, pencil-thick shoots from the previous season’s growth and label each variety carefully.
Wrap the scions in slightly damp paper, seal them inside a plastic bag and store them in the refrigerator until late September or early October when grafting conditions are more suitable.
Citrus Trees
Many citrus varieties continue ripening during August. Harvest fruit once most of the green colouring has disappeared, although tangelos often become sweeter if left on the tree a little longer.
Avoid leaving mature fruit on citrus trees for too long. Older fruit can become dry as the tree withdraws moisture, and heavy crops may reduce flowering and fruit production for the following season.
Inspect citrus trees for scale insects and sooty mould, and remove any damaged or diseased branches while growth is still relatively slow.
Feijoas
Lightly prune established feijoa trees to improve airflow and allow more sunlight into the centre of the tree. Avoid excessive pruning, as heavy pruning can reduce the following season’s fruit production.
Kiwifruit
Finish pruning kiwifruit vines as early as possible. Delaying pruning until spring can result in excessive sap bleeding, commonly known as “weeping”, which may weaken the vines.
Remove overcrowded growth and shorten fruiting canes according to your preferred training system.
Berry Fruit
Complete pruning of raspberries, blackberries, boysenberries and loganberries by removing old fruiting canes and tying in the strongest new replacement canes.
Finish pruning gooseberries and blackcurrants while the bushes remain dormant.
August is also an excellent month for planting strawberries. Prepare fertile, free-draining soil enriched with compost and position plants so the crown remains just above soil level. Protect young plants from slugs, snails and birds as growth begins.
Greenhouses and Glasshouses
Greenhouses become increasingly valuable during August by allowing gardeners to get a head start on spring planting.
Begin by removing weeds, dead leaves and old plant material that may harbour pests or diseases over winter. Clean benches, pots and glass to maximise available light.
Work compost into greenhouse beds if required and improve drainage where necessary.
In warmer districts, tomatoes can now be planted for an early crop. Many gardeners also begin sowing seeds of tomatoes, capsicums, chillies, cucumbers and other tender vegetables in trays for transplanting later in spring.
Check regularly for aphids, whitefly, slugs and snails, as greenhouse conditions allow these pests to become active well before outdoor gardens.
Pots and Container Plants
Container-grown plants often benefit from a little attention before the growing season begins.
Remove dead leaves, faded flowers and any accumulated debris from pots. Wipe dusty foliage with a damp cloth or gently hose outdoor containers to improve the plants’ appearance and maximise photosynthesis.
If roots are circling heavily around the inside of the pot or emerging from drainage holes, consider repotting into a slightly larger container using fresh, high-quality potting mix.
Apply a controlled-release fertiliser suitable for the type of plant being grown, and inspect foliage for scale insects, aphids, mealybugs and spider mites before populations increase during spring.
Ornamental Garden
August is an exciting month in ornamental gardens as bulbs begin flowering and many shrubs prepare for their spring display. A little maintenance now will reward you with healthier plants and spectacular colour over the coming months.
Roses
Finish pruning all roses before vigorous spring growth begins. Remove dead, diseased and weak stems, then shape the bush to encourage an open framework with good airflow.
Clean up fallen leaves beneath roses to help reduce the carryover of fungal diseases such as black spot.
After pruning, apply a winter spray of copper oxychloride combined with spraying oil if appropriate for your situation and always follow the product instructions.
Spread compost around the root zone to improve soil health and moisture retention, but keep mulch away from direct contact with the base of the stems.
Flowers
Prepare flower beds by removing weeds, cultivating the soil where necessary and adding compost before planting.
Continue controlling slugs and snails, which become increasingly active as temperatures begin to rise.
Sow Flower Seeds
In suitable districts, you can sow seeds of:
- Alyssum
- Begonia
- California poppy
- Carnation
- Celosia
- Chrysanthemum
- Cosmos
- Dahlia
- Delphinium
- Dianthus
- Gypsophila
- Honesty
- Marigold
- Nemesia
- Pansy
- Petunia
- Phlox
- Portulaca
- Salvia
- Snapdragon
- Sunflower
- Verbena
- Viola
- Viscaria
- Zinnia
Plant Seedlings
Plant well-established seedlings of:
- Alyssum
- Aquilegia
- Canterbury bells
- Carnations
- Cineraria
- Cornflower
- Cosmos
- Delphinium
- Forget-me-not
- Gypsophila
- Hollyhock
- Pansies
- Polyanthus
- Poppies
- Stock
- Violas
Lift and divide overcrowded perennial plants while they are still dormant or just beginning active growth. Replant healthy divisions into well-prepared soil to increase your displays throughout the garden.
Dahlia and begonia tubers can also be planted in warmer districts or started in pots under cover before being moved outdoors later in spring.
Trees and Shrubs
August remains an excellent time for planting ornamental trees and shrubs before the growing season begins in earnest.
Finish any necessary pruning of deciduous trees and shrubs while they remain dormant. Remove damaged, diseased or rubbing branches and lightly shape plants where required.
Plant new trees and shrubs into well-prepared soil enriched with compost. Water thoroughly after planting and apply mulch to conserve moisture and suppress weeds, keeping mulch clear of the trunk.
Select species suited to your local climate and available space, allowing room for mature growth to reduce future maintenance.
August New Zealand Gardening Calendar for Lawns
As soil temperatures slowly begin to rise, lawns start responding to the longer days of late winter. While growth is still relatively slow, August is an ideal time to prepare your lawn for a healthy spring.
Mow only when the ground is reasonably dry to avoid creating ruts and permanent mower wheel tracks. Keep mower blades sharp. The grass should be around 50mm (1 inch) long after mowing to avoid scalping where the grass gets cut so short it dies.
If moss has become a problem over winter, improve drainage where possible and remove excess thatch. Bare patches can be repaired once temperatures warm further in early spring.
Take the opportunity to remove weeds before they begin active growth. A little maintenance now will result in a thicker, healthier lawn during spring and summer.
Compost
August is an excellent month to make use of garden waste while preparing for the busy growing season ahead.
Build new compost heaps using a mixture of green materials such as vegetable scraps and fresh grass clippings, together with brown materials including dry leaves, shredded paper and small prunings. Adding animal manure, where available, can help speed decomposition.
Turn existing compost heaps to introduce oxygen and mix the ingredients thoroughly. Well-aerated compost breaks down more quickly and produces a richer finished product.
If your compost is dark, crumbly and no longer recognisable as its original ingredients, it is ready to spread around trees, shrubs, flowers and vegetable gardens. Compost improves soil structure, increases moisture retention and provides a steady supply of nutrients.
Pest and Predator Control
Warmer weather also signals the return of many garden pests. Taking preventative action during August can greatly reduce problems later in spring.
Continue monitoring for slugs and snails around vegetables, flowers and young seedlings. Replace baits or traps where necessary and remove hiding places such as piles of debris and weeds.
If rodents have been a problem during winter, inspect and replenish bait stations according to the manufacturer’s instructions. Ensure bait stations are securely positioned where children, pets and wildlife cannot gain access.
If ants have caused problems around your home or garden in previous years, begin placing ant baits in sheltered locations before colonies become fully active during spring. Early treatment is usually far more effective than trying to control large established nests later in the season.
Continue checking fruit trees, ornamentals and greenhouse plants for aphids, scale insects and other early-season pests. Treat infestations promptly before numbers increase.
Regional Gardening Advice
Upper North Island
Gardeners in Northland, Auckland, Coromandel and the Bay of Plenty can usually make an early start to spring gardening. Continue planting vegetables, flowers and fruit trees while soil temperatures steadily improve. Greenhouses may require extra ventilation on warm days.
Central North Island
Continue preparing vegetable gardens and complete pruning before new growth begins. Keep frost protection handy for tender plants, particularly in inland districts where cold nights are still common.
Lower North Island
Expect occasional frosts through August, especially away from the coast. Start hardy vegetables outdoors and keep tender seedlings protected until temperatures become more reliable.
South Island
Many South Island gardens remain firmly in winter, particularly inland and at higher elevations. Focus on pruning, planting deciduous trees and preparing garden beds while waiting for warmer conditions. Sow frost-tolerant vegetables under cover where possible to gain an early start.
Final Thoughts
August is one of the most rewarding months for New Zealand gardeners. Although winter is not quite over, every hour spent preparing your garden now will pay dividends throughout spring and summer. Completing pruning, improving your soil, planting trees and shrubs, and making the first sowings of hardy vegetables will give your garden the best possible start to the growing season.
Remember that New Zealand’s climate varies considerably from north to south, so always adjust planting times to suit your local conditions. If frosts are still likely in your area, be prepared to protect young plants and delay tender crops until the weather becomes more settled.
With a little planning and regular attention throughout August, your garden will soon burst into life with healthy vegetables, colourful flowers and abundant fruit as spring arrives.
More New Zealand Gardening Calendars
Continue following the Gardening NZ monthly gardening calendars throughout the year for seasonal advice on what to plant, prune and maintain, helping you keep your garden looking its best in every season.
