Growing Organic Garlic II

This article is part two of a 3-part series. The link for part one is found just below. Happy reading!

Part I: Preparing garden beds for planting in autumn & planting the garlic cloves (read here)
Part II: Weeding and liquid fertiliser feeds in spring
Part III: Summer maintenance, harvest, curing and storage of garlic (read here)

In the last article we talked about preparing the garden beds for planting garlic, the best time to plant the cloves and how to plant them. This time we will look at strategies to increase the fungal biology around the plants and on the leaves to combat rust – a major problem decimating crops for home and commercial gardeners throughout New Zealand.

As the weather warms up and we enjoy some warm days and milder nights, weeds are starting to flourish in the garden. August is a great month to get on top of weeding, so that the garlic gets maximum airflow and light to do well. This gives us a chance to check on the crop as we go.

At KoruKai Herb Farm we love eating nutritious weeds and regularly add them to salads, stir fries and smoothies. Feel free to add chickweed, puha, fat hen, miner’s lettuce, red dead nettle and speedwell to salads. The remainder can be simply uprooted and left lying on top of the mulch layer (roots facing up). If it is too wet and the roots stay wet, you may have to remove them altogether and add them to your compost pile. Garlic doesn’t like competition and by weeding the patch you also make sure that they have more airflow.

Late July at KoruKai Herb Farm, Banks Peninsula. Garlic is growing well and the beds get weeded.
We will take the netting off in the next couple of weeks.

End winter/early spring is also a good time to top up your mulch layer in order to stop the soil from drying out. It also provides food for the soil food web and suppresses weeds. Wood chips with visible fungal strands is our preferred mulching material.

Wood chips held together by visible, white fungal mycelium, make an excellent mulch material for garlic.

From September onwards we apply liquid fertiliser every 2-3 weeks until November. This is the main growing season for the garlic, so it is important to make sure they are well fed and watered if necessary during dry spells. A plant that grows well, is high in nutrients and not stresses is less likely to get attacked by diseases. We are doing preventative measures here to reduce the chances for rust early on, to make sure the plants are well fed and grow well.

For the liquid feed we make a compost extract. We use compost, worm castings and fungal inoculated wood from our wood chip pile. This provides readily available nutrients for the garlic and adds biology (bacteria, fungi, protozoa, nematodes). We particularly want to increase fungal biomass on the leaves and in the soil to out compete rust.

Humus created by microorganisms and worms in our compost pile.
A tub full of beautiful worm casting.
Beneficial fungi are grown in this wood chip pile. It takes 9-12 months to get good colonisation.

We put all the material into a large drum where we add water and stir the mixture to rip the organisms off the surface of the compost. A quick check with the microscope gives us a chance to adjust the extract on the spot.

After mixing it’s off to the home lab for microscope analysis.
A very long fungal strand (hypha) under the microscope. The thickness, the septa (divisions) and
the light tan colour are all indications that this is a good guy.
Freshly growing fungal hypha. You can see the thickened end which was once the spore.
A couple of testate amoebae are also in this field of view.

Then we filter it and apply it with a sprayer tank. In a home garden setting a 20-litre bucket, a kitchen sieve and a watering can with shower spout is totally adequate.

Dark colour after straining is an indicator for a good amount of humic acid in the compost and shows us that the compost was ready to use.

The quality of the compost extract is dependent on the quality of the ingredients. The better your compost (vermicast etc.) is, the better the liquid feed will be. We test the brew with the microscope and adjust it when necessary. We aim for a high fungal content. This will give detrimental fungi (like the rust) a hard time to get a foot hold and has worked a treat for us on KoruKai Herb Farm. If you are unsure about the quality of your compost, then please read our Thermal Compost blog.

To the extract you can also add seaweed extract, fish hydrolysate and humic acid to provide biological stimulants and additional foods for the beneficial fungi and soil organisms you are applying.

Kai spraying the garlic tops with compost extract to increase the beneficial
fungi on the leaf surfaces and in the soil.
KoruKai Herb Farm, October 2019.
Compost extract application to fruit trees before bud burst to prevent leaf curl and to garlic to prevent rust at KoruKai Herb Farm, Banks Peninsula, New Zealand. Spring 2021.

We aim for our garlic tops to be fat, great looking and fully grown until November. The bigger you can get them until then, the bigger the garlic bulb will be.

Around early November stop feeding and water them at the base (not over the leaves) only when necessary. You want to avoid having water on the leaves this time of the year as it’s the prime time for rust. Temperatures are higher than in early spring and coupled with a high humidity, makes the rust grow wild. Preferably you have high water holding capacity in your soil in order to minimise watering this time of the year. A top up of the mulch layer is also advisable before going into summer.

Some gardeners think their crop is a flop when they do not see any garlic bulb in early December. Reality is that the garlic bulb doesn’t form until the very end. So simply leave them a bit longer to fatten up. The bulb doesn’t grow gradually throughout the life cycle of the garlic, but fattens within just a few weeks. Between November and February (depending on where you live) those healthy green leaves will be starting to draw their energy and nutrients down to the base where they will create the bulb. We grow garlic on Banks Peninsula and our garlic has no bulbs in early December. Our crop starts to bulb up in mid December and the process is complete by mid/end January. Further south or up north this timing may be very different. Just observe, dig around the base without lifting the plant and see what and when it happens.

Spring is an intense time on the farm and being on top of feeding the garlic is a top priority. Make it your priority as well and you will reap the benefits.

You can follow our facebook page to get updates and photos from our crop grown at KoruKai Herb Farm. We will publish part 3 in December.

Comment below if you have questions. We are happy to help!

Coming up:
Part III: Summer maintenance, harvest, curing and storage of garlic


  • Renan Cataliotti
    28 September, 2021 at 12:37 am

    Great read as always!! thank you for the good tips
    I noticed you have some kind of black tarp around the base of your wood ship pile, is there a reason for that? do you not want the pile on soil?
    thank you!

    • Cornelia Holten
      28 September, 2021 at 2:24 am

      Hi Renan, The pile is sitting on soil. We have temporarily layed down weed matting on the outside of it to prevent twitch from growing into the pile, which is a pain when we wanna use it in the garden.


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