To all the Garlic Lovers,

Tired of having your crop lost to the rust? See below for our tried and tested recommendations for growing garlic in this new rust present system.

Here is what we have learned. First, I will share what we know about Garlic Rust:

  

1. Rust does NOT transfer to the seed, thankfully you can still plant cloves from plants that were affected with rust.
2. Rust species, Puccinia allii, lives on LIVE allium (onion, leek, garlic, elephant garlic, chive, bunching onion, and spring onion) plant matter. If you grow other alliums in the garden particularly leeks as their growing season are the other half of the year from garlic, you may find the spores will remain in your garden and re-inoculate your crop. Fortunately, once the plant dies, so do the spores of the rust fungus. My research initially led me to believe that only this specific species affects alliums, but I have seen in our garden rust spread from non-allium plants such as grass to our garlic. I now keep an eye out in spring for any rust on any plant and if it appears I try to remove the plant on a calm, no wind moment, and bag it to be taken out of the garden.
3. Rust is a fungal spore that spreads on the WIND especially in moist environments when leaves are wet for more than 4 hours at a time. The longer the leaves and any surrounding weeds stay wet the more that the rust will spread. Wet springs bring more rust than dry ones. We have successfully for the last five seasons planted our garlic up wind (from our prevailing wind in spring) from leeks and we plant our main crop garlic and elephant garlic up wind from our early garlics. This technique is very effective at limiting the spread of the spores as the wind is blowing the spores away from the plants!
4. Garlic rust has two types of spores, orange and black.  The black spores are the ones that hunker down and wait for the right climatic conditions and then start to produce the orange spores. These spread all over the leaves and significantly impact the growth of the crop by blocking photosynthesis and stressing the plant overall.
5. Plant spacing and placement in the garden is very important. Traditionally, we have planted garlic as close to 10-15cm apart in a biointensive grid pattern. Those days a long gone, as this means all their leaves are touching, and the rust can then spread like wildfire. We now plant garlic in rows at 25cm spacing, and the cloves in the rows also at 25cm spacing. We use mulch (grass clippings, hay or straw) and weed regularly to allow for as much air movement as possible so plants can dry faster. We also plant each garlic bed spread out across the whole garden with no two beds next to each other. In the past, we would have a garlic patch, this meant that if rust presented, it would soon spread to the whole plot. With the spreading out technique, if one bed gets rust, other beds don’t. In the home garden even if you are only planting a small number of cloves, I would recommend spreading them out so you don’t have all your plants together.
6. Early planting is probably the most effective thing we have done to date.  Planting your early garlics in March and your main crop garlic and elephant garlics in May gives the plants a head start on growth. By November when the spores seem to get out of hand, the crops are more developed and better able to size up, regardless of rust.
7. Variety choice is important. We have consistently found our early garlics (Early Pearl and Early Purple) to be less affected by the rust than the main crop varieties. Elephant Garlic, is actually a leek and neither leeks or elephant garlic are affected by rust, so choose wisely when planting. A failsafe choice seems to be elephant garlic.

 
Practical steps you can take in your garden:

1. Prevention is key. Once you have rust it is impossible to get rid of in an organic system.  Focus on healthy soil.  We know that healthy soil leads to healthy plants, and this is your best defence from any pest or disease. We use our home-made compost, micronized lime and liquid seaweed at planting time. We also apply Environmental Fertilisers foliar sprays throughout the season and in recent years we have used their certified organic solid fertiliser as well.
2. Do not overhead irrigate in mid to late spring. Moisture on leaves is the danger time when rust spores multiply and spread.
3. Plant your garlic up wind from all other alliums. Space your garlic at least 20-30cm apart to allow for faster drying in the crop, as the spores will travel in the wet. Spread the garlic cloves out across the garden, not all in one place even if your planting is small.
4. Clear out all other allium plant material at least two weeks prior to garlic leaf emergence. And check the garden for any pant with rust present, remove any affected plants regardless if they are an allium or not. If this is not possible, keep a very close eye on the other crops and make sure they are rust free.
5. Seed selection, we are selecting the bulbs that held up the best to the rust.  If you are holding back seed from your own stock, pick the biggest bulbs. This is good practice whether you had rust or not.
6. Planting on the day of Moon Opposition to Saturn has been recommended by Rachel Pomeroy (Organic NZ magazines Moon Calendar author until recently) as an ideal time to work with the Biodynamic calendar to help build strength against rust. Moon Opposition to Saturn is a great all-round seed sowing day as the Moon represents fertility and germination and Saturn represents form and strong structure.
7. Consider applying Biodynamic preparations to your garlic crop. Preps 501 Silica and 508 Equisetum are discussed in biodynamic circles as being able to help prevent rust. Prevention is key, so consider spraying early on in the growth of your crop, before rust presents. If you miss that boat, as we did this season, spraying after the rust arrives can also be affective at keeping it at bay.