How to Grow Garlic Successfully in NZ

Garlic is a popular and fun crop to grow. Once you have grown garlic in your own vegetable garden you can save your best bulbs from your harvest and replant them year after year if you like.

When to Plant Garlic in NZ

Garlic is planted in autumn and winter - it is widely sown between April and August in New Zealand.

Traditionally garlic has been sown on the shortest day in New Zealand (the winter solstice), but increasingly the trend is to plant earlier these days especially in the North Island. We're planting our garlic from mid-April to mid-May in 2024, and we planted our garlic during June and early July in 2023.

As rust has become an issue for growing garlic in recent years, we feel that for those in the North Island its great to get in before the shortest day to plant your garlic if you can. If you are in the South Island you have more leniency with planting later as humidity and rust is slightly less of an issue.

Storing your Seed Garlic

Store your garlic in a breathable container with fresh air and away from direct sunlight until you're ready to plant it. If growing from whole bulbs keep them intact until right before planting. If you’re growing from cloves that have already been broken up from their bulb then you’ll want to plant them sooner than later.

Preparing the Garden for Growing Garlic

Garlic is a heavy feeder that enjoys full sun and requires fertile soil to perform at its best and produce big fat bulbs. That means in order to get the best results from your garlic patch it should be planted in well-fertilised free draining soil.

We recommend preparing your garden beds in advance of planting by generously adding lots of organic matter such as aged compost, potting mix, and/or manure a few weeks in advance of sowing your garlic. A layer of mulch on top of your garden bed is also great for insulating the developing garlic bulbs from extreme temperature changes over the growing season.

If you have access to lots of free organic matter from your yard such as a compost bin or dropped leaves that's perfect for layering generously in the garden for your garlic.

If you haven't found it easy to add heaps of organic matter to your garlic growing beds then a trick employed by large commercial growers is to dig or trench down 200-300mm at planting time and add sheep pellets or guano or bone flour to the bottom of the hole/trench at a rate of roughly 100g per lineal metre (a small handful each hole). Fill in the hole/trench with loose soil to form a cushion for your garlic cloves to sit on when you plant them, leaving about 50mm from the top of the hole for planting. Plant your cloves at 200mm – 300mm apart with the pointy side up/tip up with approx. 50mm - 75mm of soil covering the planted tips of each clove, and fill your hole/trench back up.

Garlic needs lots of balanced nutrients throughout the growing season including at the very end of the season when it fattens up the bulbs. Keeping this in mind, one final trick you can try is to sprinkle a balanced bulb food or general fertiliser over the top of your planted garlic row/s at 100g per lineal metre. Preferably use a blend/fertiliser that’s not too high in nitrogen, ideally the P (Phosphorus) & K (Potassium) values are close to the N (Nitrogen) value in the N-P-K ratio, because garlic needs phosphorous and potassium to fatten the bulbs and form its protective skins.

Sowing Your Garlic

Garlic cloves are typically sown directly in place when soil temperatures are between 0°c – 10°c, however they can also be sown in trays for transplanting into the garden. Anytime in Autumn and Winter should be perfect to get them germinating.

Sow your garlic with the pointy side up about 50mm to 75mm deep, and with space of 200mm - 300mm in each direction.

The biggest and fattest cloves around the outside of your garlic bulb will typically produce the best plants, and many people choose to eat any smaller inner cloves but these can be planted too.

While growing from larger bulbs is encouraged we have it on good authority from one of the largest garlic growers in NZ that you can still produce large size bulbs from small bulbs and cloves, it really comes down to the quality of your growing medium in your garden and ensuring there are sufficient nutrients available to your growing garlic plants.

Garlic cloves should begin to sprout through the mulch in about 2-6 weeks depending on the variety and the weather conditions in your region. Be patient and do not be concerned before then. The plants may suffer some frost or a light freeze and still survive the weather.

Growing Your Garlic

Garlic does not compete well with weeds at all so its important to keep weeds under control, especially early. If you tend to them weekly or so often then weeds will be easy to remove while they’re young and they won’t get a chance to grow. If you let your garlic patch get overrun with weeds your yield will produce much much smaller bulbs.

Ensure even soil moisture by supplying 2-3 cm of water per week throughout the growing season. Then about a month before harvest you should stop watering your garlic plants to improve the keeping quality of your garlic and help the bulbs focus on swelling.

If you haven't applied a balanced bulb food or general fertiliser at planting time or there abouts, then fertilising with a balanced liquid seaweed tonic at monthly intervals (e.g. at months 3, 4 and 5) can be helpful.

Garlic Rust

Garlic or allium rust is a fungus that can really reduce the vigor of your garlic patch and it’s a common problem NZ wide now.

It flourishes with high humidity and low sunlight. Garlic rust starts as small white or yellow flecks that become darker orange or black raised spots on the leaves of your garlic plants.

Good spacing appears to be one of the simplest methods for dealing with rust, as plants spaced closely together can be devastated much more easily.

The only sure way to keep rust from your garlic is to keep it dry. A good option here is a small cloche system or if you're already lucky enough to have a greenhouse. Keeping your garlic covered will ensure it doesn't develop rust when the warm spring rains arrive.

Another trick is to always avoid watering your garlic leaves, only try to water the base of your garlic plants.

Removing infected leaves at the first sign of rust infection and binning them is also helpful - look out for small white or yellow flecks on the oldest leaves, these leaves are best removed before the rust turns bright orange.

If you spray with a fungicide at the first sign of infection you should be able to slow it down enough to get a good harvest, and if necessary repeat every couple of weeks until harvest.

Tips for avoiding garlic rust:

• Minimise water splashes onto the leaves. Avoid watering the leaves (especially if they won’t have time to dry before evening), and avoid watering your garlic plants late in the day.
• Remove and discard infected leaves if you catch rust early (look out for small white or yellow flecks on the oldest leaves, best removed before they turn bright orange).
• If you can grow it under cover to keep it dry (e.g. in a cloche system or greenhouse) this should help to prevent rust hugely.

Harvesting your Garlic

Most garlic will take about 6-7 months from planting to harvest. Note that garlic does all of its bulbing and forming of individual cloves in the last 6-8 weeks, and the first 4-5 months are just leaf growth.

You want to harvest after 2 to 4 leaves have died back and there are still 5 or 6 green leaves remaining on the plant. Don’t wait until all of the leaves have completely died back as that’s too late and your bulbs will have started to split.

Scapes are the curly flower stems that form as hardneck garlic matures, and elephant garlic sometimes does it too but not always. Cut or break them off once they curl (at about 20cm – 30cm long) and enjoy them in your next dinners.

• 'Early Purple' is a hardneck garlic that is ready to harvest about 4-6 weeks after their scapes have been removed, when the bottom 2-3 leaves have gone brown but the top 4 to 5 leaves are still green. This will be about 6 months after planting.
• 'Elephant' garlic is ready to harvest when the bottom 2-3 leaves have gone brown, remove any scapes that appear in the same fashion as with hardneck garlics (right hand side in the below image).
• 'Printanor' is a softneck garlic that is ready to harvest when the bottom 2-3 leaves have gone brown or it falls over at the neck (left hand side in the below image).
• Russian Red is a hardneck garlic that is ready to harvest about 4-6 weeks after their scapes have been removed, when the bottom 2-3 leaves have gone brown but the top 4 to 5 leaves are still green. This will be about 7 months after planting (centre in the below image).

Harvest too early and your garlic bulbs won’t be ready, meanwhile if you harvest too late you will compromise their storage quality and the bulbs will begin to separate in the ground.

To harvest your garlic loosen the soil with a shovel or pitchfork and then dig it carefully to harvest. Do not pull your garlic from the stalk or it will separate from the bulb. Gently brush most of the dirt off.

You can trim off the roots and tops with secateurs as you harvest your garlic plants or after you’ve cured them - it’s your choice.

Cure your freshly harvested garlic by laying them on wire racks or tying and hanging them to dry for 4-6 weeks in a cool, dry place out of the sun with good airflow (like a shed or garage). 

Once it had been cured store your garlic in a cool, dark and dry place and enjoy their pungent goodness over the months ahead.

If you follow the tips above we trust you'll have great success!

Happy growing!