As supermarket prices continue to rise, growing your own food has become more popular than ever. Autumn is the perfect time to focus on hardy winter crops and flavoursome herbs that will keep your winter meals fresh and productive through the colder months.
It’s also an ideal season to tackle jobs around the garden. Whether you’re keen to plant a new hedge, trim and feed existing plants, or refresh pots and planters after summer, putting in the work now will help set your garden up for healthy winter growth and a thriving spring ahead.
And don’t forget the lawn. Mild autumn temperatures still provide great conditions for sowing or renovating grass, while drainage projects should be a priority before winter rain arrives.
So, let’s get into my top gardening tips for May and make the most of the season ahead.
Growing Winter Vegetables in Autumn
A key vegetable family that produces well in winter is the ‘brassica’ group, which includes cabbage, cauliflower, and broccoli. This also includes wonderful varieties and colours such as purple sprouting broccoli and the green cauliflower variety often known as Romanesco.
Edible kale also makes an excellent addition to casseroles and soups. Plant vegetables in Premium Garden Mix which contains plenty of fertiliser to keep them growing through the colder months.
Silver beet and its decorative form, ‘Bright Lights’, yield plenty of leaves to harvest during the colder months.
Spring onions are also one of the most economical crops to grow. Anyone who has painstakingly separated each plant before dropping them into a hole will know this, because a seedling punnet with six sections can yield anywhere between 30 and 60 plants!
At this time of year, parsley and coriander also grow very successfully without bolting to seed, as they often do in the warmer months.
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Can I still sow seeds in May?
The answer is yes, but direct sowing into the vegetable garden as the soil cools won’t be as successful.
Ideally, sow seeds in trays under cover and use a heat pad to aid germination. From there, it’s better to pot up germinated seedlings into old punnets or small pots to grow on for a few weeks before planting out. Ready to Grow Seed Mix or Premium Garden Mix work well for this.
Alternatively, buy seedlings that have already been hardened off at the garden centre. Easing seedlings out of punnets should always be done with care. Ensure the roots are moist — if dry, place them in a shallow dish of water before planting. Never pull the leaves straight from the punnet. Instead, gently squeeze the plastic cell and push the plant up from the bottom.
Seedlings often fail after planting due to damage to foliage or roots. A fantastic ‘pick-me-up’ for newly planted seedlings is watering them with a diluted solution of Aquaticus Organic Garden Booster.
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Vegetable Garden Pest Control in Autumn
Sadly, white butterflies are still around the garden, laying eggs on the leaves of brassica plants. Once hatched, green looper caterpillars eat their way into the smaller leaves, causing a lot of visible damage. Hoping they’ll simply die off as the weather cools isn’t working just yet! Either pick them off by hand or use a caterpillar pesticide. Check plants every few days — when the sun is on the plants, the caterpillars are easier to spot.
It’s not just caterpillars enjoying all the fresh vegetable growth — slugs and snails love it too. Three control options work well: snail bait, a dish of beer half-buried alongside the plants, or ‘digital’ control after dark using a torch.
And a final word on baby snails — take a close look at the developing hearts of young cabbage plants. Baby snails crawl into them and happily munch away on the newest leaves!
Essential Garden Jobs for Autumn
How to Plant a Hedge in Autumn
Whether you’re captivated by photos of beautifully trimmed hedges or simply need more privacy, autumn is a very good time to plant one.
Tall hedging plants include sasanqua camellia, karo, eugenia, corokia, and griselinia. For small to medium hedges, use lavender, rosemary, blight-resistant forms of buxus, and lower-growing corokia.
Dig holes twice the width and at least the same depth as the plant pot. If the soil is clay, throw a handful of Gypsum into the hole first, followed by two Tree and Shrub Fertiliser tabs and a layer of Premium Garden Mix. Place the plant’s root ball on top and fill the hole with layers of Garden Mix and existing soil. Firm the plant in using your feet and stake it if the area gets plenty of wind. A layer of mulch on top will help keep the soil moist while the plant establishes and will also deter weed growth.
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Refreshing Pots and Planters After Summer
The investment in feature pots, potting mix, and plants is often a significant part of the garden budget. Everyone wants them looking good all year round, but autumn is the time to do the pot ‘housework’.
Weed the surface area and lightly trim plants by removing dead growth and reshaping where needed. Remove any dead plants entirely. Over summer, the potting mix often contracts, so add a layer of Premium Compost or Premium Garden Mix to nourish the plant and cover exposed roots. For larger pots, water in half a bucket of liquid fertiliser, such as Aquaticus Organic Garden Booster or Biofert Moana Natural, mixed according to the directions.
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Best Time to Trim Evergreen Trees
Autumn is a good time to trim evergreen trees. Unlike deciduous trees, which lose their leaves in winter and are easier to prune when bare, evergreen magnolias, michelias, and most NZ native trees should be worked on now rather than during the colder months.
This also includes evergreen fruit trees that have finished fruiting or are not currently producing fruit, such as citrus, avocados, olives, feijoas, and tamarillos. Spread pelletised sheep or chicken manure around the base of the tree to break down over the coming months and add nutrients to the soil ready for spring growth.
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Lawn Care in Autumn – Repair, Renovate & Improve Drainage
Lawn Repair and Maintenance
With winter around the corner, don’t neglect the lawn. Patching or sowing new lawns can still be done in these moderate temperatures. For best results, use Premium Lawn Soil - see the healthy germination photos below where we sowed Prolawn Tournament Blend Grass Seed.
I highly recommend using Prolawn Lawn Starter Fertiliser along with the lawn seed to encourage strong growth.
While autumn leaves create a colourful carpet across the lawn, they also become soggy with dew and rain, trapping moisture underneath, which can kill healthy grass. Put the leaf blower or rake to work regularly.
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How to Improve Lawn Drainage
Poor lawn drainage becomes more obvious in winter, especially after periods of heavy rain. Take preventative action in areas that become muddy and where grass dies off. Often, this is caused by compacted clay beneath the lawn surface.
For many areas, applying gypsum now and again in a few weeks can help break up the clay and improve water penetration. In more severe cases of pooling water and mud, we recommend installing drainage to direct water away from the lawn area to a lower part of the property. Check out our handy guide on Installing a Field Drain to learn how to ‘wrangle’ the water pooling on your lawn.
How to Grow Free Plants this Autumn
Many common plants reproduce naturally by dropping seeds that germinate nearby. Garden favourites such as hellebores, dietes, euphorbias, and gaura are now emerging as future plants for the garden. NZ trees and shrubs such as griselinia, golden Tainui, akeake, as well as NZ and exotic grasses, also tend to produce ‘babies’. Lift and pot them up with Premium Garden Mix or Potting Mix until they reach a good planting size.
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Preparing Summer Plants for Winter – Putting the Summer Darlings to Bed
In Auckland and Hamilton, there’s no single right answer as to whether dahlia tubers should be lifted and stored over winter. However, leaving them in the ground can make them vulnerable to a wet winter, which may cause rot.
Ideally, lift and dry them, brush the soil off the tubers, and store them in paper bags or cardboard boxes. Labelling them also helps. Don’t divide the tubers until planting time in October, when it’s easier to see which pieces are still viable.
