August Gardening Tasks
August can be a real swing month in the garden, with winter conditions lingering in some parts of New Zealand while others start seeing the first signs of spring. Days are getting longer and plants are beginning to respond, but cold snaps, wet soil and frosts can still catch gardeners out. This month is about working with the weather you have and getting ready for the growing season ahead without rushing it.
Sow, Plant and Keep Veggies Coming
Keep harvesting winter vegetables as they mature and clear away crops that have finished to make room for new plantings.
Where conditions suit:
SOW Beetroot*, broccoli, cabbage*, carrots, celery*, endive, lettuce, peas, radishes, silverbeet, spinach, turnip*. Note: *in warmer areas.
PLANT seedlings of asparagus, broccoli, cabbage, lettuce, peas, rhubarb, silverbeet.
Use succession planting eg: staggering plantings every few weeks so crops mature at different times, and you can keep harvests coming.
Where the soil is workable, prepare empty growing areas before planting with Daltons Garden Time™ Compost or top up raised beds with Daltons Garden Time™ Vegetable Mix.
Image credit: savs_organic_produce
Crop Rotation Planning
When planning your summer garden, remember to rotate vegetable families around the garden where possible rather than growing the same crops in the same spot each year. Crop rotation can help reduce the build-up of soil-borne pests and diseases.
Get a Head Start on Spring Seeds
August is when many gardeners start thinking about sowing seeds for the growing season ahead.
Veggies
If you have a warm, bright and protected growing space, tomatoes, chillies and capsicums can be started indoors or under cover now to give them an early start. There’s no need to rush though. In cooler parts of New Zealand, or if you don’t have somewhere consistently warm and well lit, these summer vegetables can wait until September.
Flowers
Start sowing flowers indoors, varieties include alyssum, aquilegia (granny’s bonnet), asters, cornflowers, cosmos, hollyhocks, larkspur, Livingstone daisies, lobelia, marigolds, petunias, portulacas, salvias, scabious, sweet peas and zinnias can all be started from seed now.
For successful seed sowing
- Fill clean seed trays or pots with Daltons Premium Seed Mix.
- Check the seed packet for the recommended sowing depth and germination requirements.
- Keep the mix evenly moist but not overly wet.
- Provide suitable warmth while seeds germinate
Seedling care
- Once seedlings emerge, give them plenty of light to encourage strong, compact growth.
- Thin out weaker seedlings as they develop so the strongest plants have room to grow.
- Keep tender seedlings protected until outdoor temperatures are suitable for planting. Cold nights and frosts can continue well into spring in many parts of New Zealand.
Top tip: Growing requirements vary between plants, so always check the seed packet before sowing.
Get Potatoes Started for Christmas
Potatoes are easy to grow and a great choice for beginner gardeners and families. A little preparation before planting will help get them off to a strong start.
If you want potatoes ready for Christmas, plant early-cropping or shortcrop varieties in early spring, or from late winter in warmer areas. These varieties mature quickly, within around three months.
Long-crop or maincrop varieties can be planted in mid-to-late spring for a heavier harvest in late summer and autumn. Read our guide below for long-crop varieties.
Start chitting to give them a head start
Place certified early-cropping seed potatoes in a dry, well-lit spot for 1–2 weeks before planting, until short, sturdy sprouts around 2–3cm long appear.
Choosing your planting site
- Choose a sunny spot with fertile, free-draining soil. Before planting, mix Daltons Garden Time™ Compost or Daltons Premium Garden Mix through the existing soil.
- Choose a different area for potatoes from where you grew them last season and avoid planting where tomatoes, eggplants or capsicums have recently grown, as they can share pests and diseases.
- No space? Potatoes are easily grown in large containers or grow bags. Use Daltons Premium Garden Mix or Daltons Garden Time™ Vegetable Mix and make sure the container has good drainage.
Feed Garlic
Once garlic is showing good green growth above the soil, it is actively growing and ready for a feed.
Apply Daltons Premium Bulb Fertiliser according to the pack directions once shoots have emerged, then feed again in mid-spring to support bulb development.
You can also supplement feeding by adding Garden Time™ Seafeed Plus NPK to your water and applying every 2–3 weeks.
Get Fruit Trees Ready for Spring
Refresh mulch around established fruit trees where needed to help suppress weeds and conserve soil moisture as temperatures start to rise.
Keep mulch clear of the trunk rather than piling it against the bark, as this can increase the risk of rot.
Citrus harvesting can continue as fruit matures. Tangelos can colour up and look ripe before they have developed their best sweetness, so leave them on the tree longer if needed.
Rose Care
Check Climbing Roses
With new spring growth not far away, check climbing roses are still securely attached to fences, wires or other supports. Replace damaged ties and loosen any that have become too tight, so they do not cut into stems as new growth begins.
Finish all Rose Pruning
If you haven’t finished your rose pruning yet, now is the time to get onto it. Watch how to prune roses.
Remember to clear away old leaves and pruning debris from around the base before fresh spring growth gets underway. Leaving infected leaves and pruning debris around the base can increase the risk of pests and diseases carrying over into the new season.
Quick Answers
What should I do in the garden in August in New Zealand?
August is a good time to start preparing for spring. Keep winter vegetable crops productive, get early potatoes ready for planting and start selected vegetables and flowers from seed indoors or under cover if you have suitable growing conditions.
What vegetables can I plant in August in New Zealand?
Depending on your region and conditions, you can sow crops including beetroot, broccoli, cabbage, carrots, celery, endive, lettuce, peas, radishes, silverbeet, spinach and turnips. Seedlings of crops including asparagus, broccoli, cabbage, lettuce, peas, silverbeet and rhubarb can also be planted where conditions suit.
Can I start tomato seeds in August in New Zealand?
Tomatoes can be started indoors or under cover in August if you can provide consistent warmth and good light. In cooler regions, or without a suitable protected growing space, there is no need to rush and seeds can be started in September.
Can I start capsicum and chilli seeds in August?
Gardeners with a warm, well-lit indoor or protected growing space can start chillies and capsicums from seed in August. Keep seedlings protected and do not plant them outdoors until conditions are warm enough and frost risk has passed.
Can I plant potatoes in August in New Zealand?
In warmer areas, early-cropping potatoes can be planted from late winter. In cooler or frost-prone parts of New Zealand, August is a good time to start chitting seed potatoes and prepare the growing area for planting once conditions improve.
What is chitting potatoes?
Chitting is the process of encouraging seed potatoes to develop short, sturdy sprouts before planting. Place certified seed potatoes somewhere dry and well lit for around 1–2 weeks until sprouts approximately 2–3cm long appear.
Can I grow potatoes in bags?
Yes. Potatoes grow well in large containers and grow bags, making them a good option for smaller gardens. Choose a sunny position, use a quality growing mix and make sure the container drains freely.
When should I fertilise garlic in New Zealand?
Feed garlic once the green shoots have emerged and the plants are actively growing. Apply Daltons Premium Bulb Fertiliser in late winter or early spring, then feed again in mid-spring to support bulb development. Avoid feeding once bulbs are close to maturity. You can also supplement feeding with Garden Time™ Seafeed Plus NPK every 2–3 weeks.
What flower seeds can I sow in August in New Zealand?
Flower seeds that can be started indoors during August include alyssum, aquilegia (granny’s bonnet), asters, cornflowers, cosmos, hollyhocks, larkspur, Livingstone daisies, lobelia, marigolds, petunias, portulacas, salvias, scabious, sweet peas and zinnias.
Why should I rotate vegetable crops?
Crop rotation means growing vegetable families in different parts of the garden from season to season. It can help reduce the build-up of soil-borne pests and diseases associated with repeatedly growing the same crops in one place.
