Growing Organic Garlic Part I

Part I: Preparing garden beds for planting in autumn & planting the garlic cloves
Part II: Liquid fertiliser feeds and weeding in spring (read here)
Part III: Harvest, curing and storage of garlic (read here)

I love growing garlic. I get a huge satisfaction when pulling the crop and seeing the fat heads after all the hard work and the long growing season. We often get asked what we do to get this great result without pesticides, herbicides, chemical fertilisers and above all fungicides to combat rust. So here I share what we do at KoruKai Herb Farm. This is the first part of a series. Other parts get published throughout the season (see above).

I have training in Organic Horticulture through AG New Zealand and have built on that knowledge through observation and by simply doing it. I have also pretty thorough knowledge of the soil food web through a course by soil microbiologist Dr. Elaine Ingham. I say “pretty thorough”, but in reality the soil food web is so utterly complex and still so unknown to scientist. It is a hot topic of research and I will keep learning! The below is my way of doing things with the experience that I have gained through growing garlic for 10 years now. This is by no means the only way and this also does not exclude other ways to go about it. I might myself change it as time goes by as I find other or better ways to do it.

Rust is a big problem in commercial operations and home gardens so I want to explain our philosophy and the basics for a great crop with the rust in mind. I try to not be too scientific.

First of all I need to say that we are on Banks Peninsula on the South Island of New Zealand. Timings are specific to our growing conditions and you need to adjust your timing to your climate. We have grown crops on the farm for 7 seasons and have adjusted the planting and harvesting time over the years to suit the crops. For example in the far north you can probably plant garlic in June/July and get the same results as we do and in the far south you may want to plant them as early as March/early April.

We basically apply 2 strategies to get a great crop:
1. ) Plant early to give the plants time to grow to a good size before winter.
2. ) Prepare the soil with extra food supply for the long growing season ahead and apply liquid food throughout the spring period.

By planting early the garlic plants have a great start in early spring when temperatures warm up and grow to a decent size before rust season arrives with warm humid weather in late spring/early summer. A big, strong leafy growth before summer enables the plants to form a big head between November and January. Planting the garlic late would mean that the garlic is still pretty small in late spring and might not achieve a big size. Then it may get hit by disease in early summer, which can diminish your crop and will not enable the plants to put out a big head. If you have had garlic rust or other types of rust in your garden before, then the chances are high that you will see it again. So it is best to be proactive about it and learn how to still grow a decent crop.

Choose a sunny position for your garlic crop and if you have had rust in previous seasons then rotate your beds. Garlic likes fertile, well drained, moist soils, but does not like waterlogged conditions. So choose your bed/s carefully to avoid water logging during winter.

We prepare the soil for planting around 2-4 weeks before we intent to plant the garlic so it can settle. In my opinion simply applying compost and well rotted manure at planting time is not enough as the nutrients will be used up at the end of winter leaving the plants with not enough food for the main part of the growing season.

We have a heavy clay soil so again you need to adjust what you do suited to your soil conditions. We dig a tench in the middle of the double reach garden bed. About 1.5 spades wide and 1-1.5 spades deep along the whole length of the garden bed.

Trench about 1.5 spades wide and 1-1.5 spades deep

We add food scraps from the bokashi buckets, along with wood chips and chicken manure, some seaweed and autumn leaves. We also add fresh roadkill if available, slaughter waste from our self-sufficient farm or possums from the trap. Do this only if you feel OK to do so. I was grossed out when someone suggested that 10 years ago and now I am fine with it. There is nothing left at harvest time, I promise.

Filling the trench.

If you don’t have a bokashi composting system you can simply use food scraps and other organic matter you can get your hands on. Try to balance high nitrogen material with enough carbon material. Try to use fresh material that has not been composted. The reason for this is that it will break down over time by bacteria, fungi, protozoa and earthworms and will release nutrients later in the season. Those nutrients are still bound in the fresh plant material and cannot leach away by the winter rains. This is the food for the garlic for spring/early summer and we have had great results since applying this method. By doing a trench you are not disturbing the soil on either side of it, therefore the soil food web and fungal mycelium stay intact there and do not get disturbed by digging. The microorganisms have then a chance to spread from those areas back into the middle to break down the massive amount of food supply.

When we started breaking in the heavy clay on our property so we could plant crops, we did double digging and added bokashi content into lower section. Now we are more and more moving away from disturbing the soil and therefore the soil food web. We now bury bokashi only when absolutely necessary when a) the soil needs it or b) the crop needs it. Most of our bokashi contents get added to our monthly compost heaps that we make with autumn leaves, garden waste, humanure, grass clippings, seaweed, etc. I will do a separate post on composting and bokashi composting.

The trench is filled 3/4 high with the plant materials and then the soil is shoveled back on top.

I then add a good layer (about 5 cm) of high quality, bio complete compost with a high proportion of beneficial fungal strands. Sorry for being scientific here, but this is essential! Bio complete means a high amount of bacteria, fungi, protozoa (flagellates, amoebae) and some beneficial nematodes to do nutrient cycling in the soil, along with worms and other decomposers and shredders.

Compost and some worm casting is out over the soil. It is simply put on top without digging it in.

We use a microscope on the farm and test the compost for those qualities. I cannot give you more details in this post, but I just want to stretch the point here that one compost is not the same as another compost. Most compost you get in bags at the garden center are low in those numbers and are not that great. Again this is my opinion and you may find good quality compost from a landscaping supplier, I just haven’t come across one. Making your own compost with garden waste, manure, seaweed, autumn leaves, biochar, wood chips and food scraps is essential for a great success in organic gardening and needs to be the highest priority and not be a simply exercise to get rid of garden waste.

Beautiful humus created by microorganisms and worms in our compost pile.

If you are unsure how to go about making great compost, join a local garden club or visit one of our compost making workshops.
To the compost, we also add a sprinkle of worm castings and biodynamic cow pat pit. The latter is available from Rachel Pomeroy at Grow Biodynamic.

A tub full of beautiful worm castings.

You can also add well rotted manure if you don’t have enough compost or worm castings. For next season we recommend you make compost and get a worm farm started. Lots of fun and such a great resource for the garden. We prefer to compost manure first and add the manure with the compost. Manure can be added to the worm farm as well and potential pathogens in the manure are killed either by the high temperatures in a thermal pile or by travelling through the digestive tract of the worms several times. This makes manure safe to use.

The compost layer is the one the cloves will get planted into and provide instant food for the developing garlic plants. The roots and leaves as they develop will pick up the beneficial organisms from the compost and the plants will feed them by putting out sugars produced though photosynthesis. The bacteria and fungi on the other hand feed the plant with nutrients from the organic matter and the soil. I mentioned earlier that we want the compost with lots of fungal strands. The reason for this is that beneficial fungi will grow on the leaves and roots of the garlic and effectively cover the leaf surface. Under the right microscope you won’t be able to see the leaves of the plants, you will see them covered in bacteria and fungi. This cover makes it hard for detrimental fungi to take hold as they simply will have a hard time to get past the beneficial fungi. A compost high in carbon materials (brown autumn leaves, bark, wood chips, straw) will grow lot of fungi. An inocculation with forest soil may be necessary if you lack beneficial fungi in your system.

A very long fungal strand under the microscope. The thickness, the septa (divisions) and
the light tan colour are all indications that this is a good guy.

Now that you have applied all the food and compost, you need to add a decent layer (about 5 cm) of mulch material.

Wood chips go over the compost.

Depending on the material, this can be applied after you have planted the garlic. I tend to do it before so the garlic has a better chance to grow through it when I pushed it a wee bit to the side where I plant the garlic clove. The mulch layer suppresses weeds, protects the top compost layer from the winter rains and also acts as another food source as it breaks down. A good choice is wood chips from a wide range of trees, organic pea straw (it needs to be organic as otherwise you are adding herbicides, fungicides and pesticides to your system and effectively preventing the soil food web from functioning properly), grass clippings and garden waste like shredded corn. More ideas can be found here.

Beneficial fungi are grown in this wood chip pile. It takes 6-9 months to get good colonisation. This material makes an awesome mulch material as it is brimming with beneficial fungi to outcompete the bad guys like rust, club root, mildew and other fungal diseases. We also add this to the compost when we build the heap to inocculate it with those fungi.

I generally let the bed rest for 2-4 weeks, but you can also plant straight into it if you are running out of time.

Bed is ready to go for planting time.

Now comes the fun part: Planting the garlic!

When buying seed garlic choose a trusted supplier that sells high quality cloves/heads. We have a limited supply available and we hope to have more in the years to come as we extend the garden areas. For now we cannot grow more than 1000 heads per year. If you have grown garlic last year, then choose the best heads and from those the best cloves for planting.

Space garlic 10-15 cm (elephant garlic about 20cm). Simply make a wee hole about 5 cm deep into the mulch and compost layer and push the cloves into the hole with the pointy end up and the flat end down. Cover with compost and do the next one. You can also leave the hole open until you have planted them all, therefore you don’t forget where they are and get the spacing right.
I make myself a wee planting stick or cardboard piece as in the photo below which is 12.5 cm long and then it is easier to get the spacing right. A wider spacing gives the plants more room and airflow and is beneficial if you have had garlic rust in your garden before or don’t have heaps of nutrients in the soil. If you haven’t applied the mulch yet do this now, but make sure to use loose material so the garlic can push its way through it.

Planting garlic at KoruKai Herb Farm, New Zealand.

We have an abundance of birds on the farm and because we have added fresh compost with lots of worms, they will come in and scratch around in search for those lovely juicy worms, unearthing cloves as well or damaging young seedlings. We therefore have to cover all the freshly prepared and planted beds with bird netting. We use number 8 wire, cut them to length and bend them to a hoop. We simply stick them into the ground on either side of the garden bed. Then the bird netting gets draped over and stapled into the ground with pegs we make from the same wire. You don’t have to do this step if you don’t have blackbirds or free range ducks. Just observe what’s going on over the first week or so and take action if you have to.

Freshly planted seedlings get covered with bird netting to prevent birds from scratching up the worms in the
compost sitting just under the mulch layer.

During planting and preparing the bed you may have observed that the soil was moist or dry. If it has been dry then go ahead and give the bed a deep soak with the hose after planting. This is generally not necessary this time of the year, but it might be in your situation/climate.

Now you can watch the garlic shoots emerge after 4-6 weeks. There is nothing that needs doing over the winter period. Sit back and relax until spring.

You can follow our facebook page to get updates and photos from our crop grown at KoruKai Herb Farm. We will publish part 2 in August.

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

Coming up:
Part II: Liquid fertiliser feeds and weeding
Part III: Harvest, curing and storage of garlic


  • sego
    2 August, 2021 at 4:57 am

    Hi Cornelia,

    is there any risk of getting bad bacteria in the soil by burying meat and dead animals? I would love to learn how to recognise bacteria, fungi etc on a microscope, is that something you teach in your workshop? thanks

    • Cornelia Holten
      2 August, 2021 at 7:35 am

      Hi Sego, A healthy soil food web will break down carcasses, making nutrients available for plants. When buried shallow enough the topsoil is a very active place. Buried too deep and you won’t get them to break down fast. You also want it to be in an area with enough available oxygen, because bad bacteria (pathogens) thrive in low oxygen conditions. Do this in moderation and not add too much as meat is high in nitrogen. You can also compost this material first.
      Yes, we do teach microscope analysis of compost, soil, compost extract and tea. I am teaching the organic students at the BHU at Lincoln university and will soon make this course available for others as well. You can find more info and sign up to get notified once it is offered here:

      • sego
        9 September, 2021 at 5:23 am

        oh great! That s amazing! I would love to join if I can make it!!
        Would you be able to explain what happens when we do a non-aerated compost tea with or without molasses? Is that never recommend for plant health? 🙂 Thank you for all your answers, that is so kind !

        • Cornelia Holten
          9 September, 2021 at 7:03 am

          When making compost tea the goal is to multiply microorganisms (bacteria, fungi, protozoa) and then spraying them onto your crop. Those organisms are aerobic organisms that thrive at 6ppm of oxygen or higher. In reduced or no oxygen conditions those critters cannot live, they will either go dormant or die right off, all your fungi will be wiped out and that’s the ones we need for disease protection. At reduced oxygen conditions you are multiplying pathogens (thrive at 4-6ppm) and disease causing organisms, which we of course do not want. You can clearly observe the changes in a compost tea with a microscope and you will have to be super careful to wash hands after touching such a liquid.
          Hope that helps. Do reach out if you have further questions about my blog.

          • segolene timmery
            10 September, 2021 at 9:39 pm

            Last year, I followed guidelines on making EM (effective microorganisms ) for the veggie garden (also used in Bokashi). Recipe used molasses to multiply microorganisms and it was recommended to stir it only once a day. I thought the final product was quite attractive and had a pleasant sweet smell. But after reading your blog, I have made some research on the soil food web, I have read that molasses should not be used as it is food for bacteria and aerated compost tea is what is beneficial for the garden. I was a bit confused and not sure if what I have been doing is actually harmful! I would love to be able to see on a microscope what I am brewing 🙂

          • Cornelia Holten
            11 September, 2021 at 7:46 am

            You need to be aware that EM is anarobic organisms, so a totally different approach. Not wrong, just different.

  • Candice
    28 July, 2020 at 4:58 am

    Do you know where I can buy organic pea straw? Or should I just grow my own?

    • Cornelia Holten
      28 July, 2020 at 5:59 am

      Hi Candice, You’d have to google your closest supplier or contact certified organic farms in your area. In my area you could use Milmore downs. They have bales of rye straw for sale at the moment. Simply go to their website.

  • Andrea
    22 April, 2020 at 6:26 pm

    Great post, thank you for all your effort and wisdom.

  • Judith Inzunza
    18 April, 2020 at 11:55 pm

    Hi Cornelia
    Thanks for your post. I am really struggling to make enough compost to keep me going through the year. Just a question about using manure in the worm farm.. If there is pyralid in horse manure will putting it through a worm farm get rid of it? I know from bitter experience that composting it doesn’t.
    Judy Inzunza

    • Cornelia Holten
      19 April, 2020 at 4:00 am

      I have no experience with pyralid, but if it doesn’t break down when composted it is likely to not break down in a worm farm. Also care needs to be taken to not feed worms with manure that is from animals treated with a anti-worming drug, that would kill them. We only use cow manure from our farm and we do garlic and apple cider vinegar tonics to treat internal parasites, so that’s fine to use.

      • Judith Inzunza
        19 April, 2020 at 6:26 pm

        Thanks for that.

  • Janine Heeringa
    17 April, 2020 at 2:57 am

    Cornelia this is an excellent system. I have really good compost now so wondered why last season’s garlic was still pretty small. The trench is definitely the answer. Will try it this year and also an earlier planting. I had a lot of problem with rust last year as well. Fingers crossed.

    • Cornelia Holten
      17 April, 2020 at 3:58 am

      Are you able to use a different bed to give it as much distance as you can to the rust infected one? The spores will be all over the bed and surrounding area and then it’s pretty hard to get on top of things. Hope things grow better this year for you. We got challenged with rust 2 years ago with a very wet and humid November/December. Last year was good with this system. We will keep experimenting and learning. There is no right or wrong way.

  • Doug rule
    17 April, 2020 at 2:30 am

    How does peat soil go

    • Cornelia Holten
      17 April, 2020 at 2:40 am

      I have never grown in peat, but I assume it has more organic matter content than heavy clay? You may have to do your own experimenting, but if it is pretty fertilie you may be fine by adding just compost to feed the crop. But I cannot say for sure. Maybe someones else has an idea?


Leave a Reply