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. 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 straight away.
Sowing Your Garlic
Garlic is a heavy feeder that requires fertile soil to perform at its best; to get the best results from your garlic patch it should be planted in well-fertilised, free draining soil.
You can prepare your garden beds early by adding some organic matter like aged compost or manure and mulch a few weeks in advance of sowing your garlic. When it’s time to plant we highly recommend digging or trenching down 200-300mm and adding sheep pellets or guano or bone flour to the bottom of the hole/trench at a rate of 100g per lineal metre (roughly 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 about 50mm deep (so that approx. 50mm of soil covers the planted tips of each clove) and fill your hole/trench back up.
We then recommend sprinkling 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 slightly higher than the N (Nitrogen) value in the N-P-K ratio.
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.
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 and ensuring there are sufficient nutrients available to your growing garlic plants.
Garlic cloves should begin to sprout through the mulch in about 4-6 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.
Fertilising with some liquid feed (e.g. seaweed tonic) at monthly intervals (e.g. at months 3, 4 and 5) can be helpful during growth but be careful not to over apply nitrogen.
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. It 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. If not one trick is to always avoid watering your garlic leaves, and only try to water the base.
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.
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.
- 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).
- 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).
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 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).
Store your cured garlic in a cool, dark and dry place and enjoy their pungent goodness over the months ahead.