Rust is an airborne, parasitic fungi that makes your plants look, well – rusty! The raised, orangey spots cover the foliage quickly when conditions are ideal and in a severe case, the leaves yellow, shrivel and die. With the foliage unable to convert energy in its usual efficient style, bulbs are small, but still edible. And, by the way, all good for seed the year following.
Rust is an environmental happening – a coinciding of perfect temperature and moisture, so dont feel bad that your plants are rusty. Its not your fault!
Wet foliage and mild temps create the perfect environment for spores to multiply, making spring a rust prone zone. If the weather is on your side and heats up and dries out the fungi will slow right down, if not… bad luck!
It’s an environmental thing, you see, exacerbated when nutrition isn’t met, soils are overfed or poorly drained or weakened with artificial fertilisers.
Prevention
Airborne fungi, like rust are impossible to manage, so its smart to get out ahead of it and put your best prevention foot forward. These are my current tried and true ways.
Plant early. March or April plantings give you the best shot, by ensuring bulbs are developed and sized up when rust hits in spring.
Free draining, nourishing soil is key. Heavy clay (wet feet) and likewise poor sand (too dry) are the most susceptible. No surprises there, as mineral uptake is poor in both situations. Sound nutrition will always put you ahead of the game no matter what problem you are dealing with. Over doing nitrogen in your bed preps feeds rust like crazy, so stick to good old homemade compost.
Mix up your plantings. Plant alliums (chives, leeks, onions etc) away from each other as is practical. Plant garlic in little groups about the place rather than in one block. It fascinates me to watch some little plots go rusty while others remain rust free – a small victory for diversity!
Space well. Studies that show rust is minimised with good air movement, seem to be on the money. There is a trade off though – bigger spaces = more room for weeds and mean less crop. Its something to bear in mind and experiment with.
Milk or Herb Teas. Milk is a wonderful fungal prevention spray. Dilute it 1:10 and pour on once a week. Or just rinse out milk bottles and pour those on, as and when. Fermented stinging nettle or horsetail tea make for robust cells and strong leaf cuticle – just what the doctor ordered.
Biological Fungicides. Botryzen sprayed on emerging shoots saves the day! Way too late once rust is in – perhaps order your bottle now in preparation for next season.
Crop Rotation. Leave as long of a gap as you can before growing alliums on the same bit of ground again.
Regular EM and seaweed foliar sprays. Rather than vainly trying to ‘kill’ off the fungal spores (they’re everywhere!) – outcompete them by filling the space with ‘good’ guys.
Mulch. No matter what the question, mulch is always the answer. Prevent fungal splash back and nourish the soil.
What to do when rust hits
Trimming off infected leaves seems to help slow the spread, but really those fungal spores are everywhere! Dose the crop in EM + nettle after foliage removal.
Crop removal. Hardcore I know, but if your crop is absolutely covered in rust and the bulbs are still undeveloped – there really is no point, they wont be growing fatter so may as well get them up. In this instance, remove the rusty leaves and mince everything up tops and all. Dehydrate or freeze for an awesome stash of ready to use garlic.
Garlic alternatives
Sometimes its good to take a break from a crop if its been a struggle. How about supporting an organic, local grower and buying garlic in next year while you give your garden a rest from it. Practice making epic compost instead – it really will save the day!
- Garlic chives provide a mild garlicky hit if tossed in at the end of cooking.
- Elephant garlic (being a leek and all) wont come down with rust like true garlic does, so this is an option as a roasted vege. The flavour is barely garlic but it looks just like one and your friends will be impressed at the size.
Thanks for sharing this information and your thoughts. It’s so frustrating aye. I took a break from garlic this year but will try again next year. I imagine you’re familiar with Charles Dowding’s YouTube channel. He put up a garlic video recently and also mentions rust as increasingly difficult to manage. From memory he said he has much better results growing under cover.
Yes Kirsty – I’m looking forward to cracking garlic under cover. It’ll be tricky to provide airflow as well but through trial and error we’ll find a way. I’d pop it in my greenhouse a la Charles 🙂 but it’s way too hot for the final months of finishing for it. 6 months to ponder and hatch a plan! Thanks for writing in
best Kath
Hi Kath. Last year my garlic got the dreaded rust which decimated my wee crop, so this year, i decided to plant it in a large container away from where I planted it last year…and same story..the rust has just started. So after searching the internet, I read about Condys Crystals….i.e. Potassium Permangate. An old fashioned remedy and tonic and is supposed to help rust and curly leaf.. So today, I sprayed my garlic and peacherine..rate is 1/4 tsp per litre of water. Then you drench the soil around the plants to kill any spores in the ground. Fingers crossed. Will let you know if it works. Makes me wonder what toxic sprays commercial garlic growers use to,prevent the rust as its a worldwide problem it seems. Kind regards, Claire . Palmerston North
Yes, its a tricky beast alright. The vicious cycle we find ourselves in here is that when we kill of the bad fungi we also kill the good, leaving our crops more and more vulnerable requiring more and more fungicide. Yes I’ve read Wallys article about Condys crystals (kill mode here too I’m afraid) and would love to know how you go with it. For me I’m looking to outwit it without the killing mentality, rather a building one. But it’s all theory at the mo and we are all learning here together. I appreciate you taking the time. Stay in touch with how you get on.
kind regards
Kath
I think you’re on to something with the rain cover.
First year I planted garlic it was under a tunnel of frost cloth to protect the plants from the westerly winds. It still allows some water through for the plants and liquid fertiliser teas.
I got rust much later then everyone else and only after the covers had been removed.
great thanks for sharing that David 🙂
Thanks for confirming and helping us to keep positive. First garlic season in lower North Island NZ after growing great enormous, wonderful garlic in Victoria, Australia. We did EVERYTHING on your suggested list, as we’d heard garlic rust was rampant in NZ and so had researched. This week, vicious wind, followed by drizzle, grey, damp and more wind. The entire 400 plants are covered in rust, since Wednesday this week. Today Friday.
The cover was taken off a few weeks ago 🙁
We’re going hardcore, as you did. Harvest the lot, process by dehydrating, freezing and maybe some in Verdurette (basically anything green 4 parts to 1 part good salt.
And we’re moving to the Hawke’s Bay (a little bit unexpectedly) in two weeks, so the silver lining is we won’t have to come back to harvest the garlic at the end of December. And hopefully will leave the garden clean of as many spores as possible for the next people to take over and use the beautifully prepared and nutrient dense soil! (Hard leaving a garden!)
Thank you, helps with the pain of loss!!
Tricky beast this rust business – thanks for sharing Fiona, though sorry for the pain 🙁 Fingers crossed for rust free in your new abode.
best
Kath
Be careful planting in the berry patch. We have raspberry plants that have got rust the last two years at exactly the same time as the garlic.
Some Oxalis species can harbour the spores overwinter too.
A timely comment Aimee – I have rust in the berryhouse, not on my raspberries but in my herbal border on the marshmallow – it’s really going off at my place at the mo, so yes no garlic in the berry house!
Hey Kath,
So. Looks like I have late rust. Popped up a week ago and we are so close to solstice harvest time I have just kept an eye but mostly left it. Usually I leave my bulbs in until the tops are super dry and droopy. They aren’t yet. Theory being the bulbs fatten further as they suck the goodness from the leaves. But I should probably pull ‘em now eh? Will I gain anything by letting them stay a while? I don’t have any other alliums apart from chives.
Hey Lee, You did well to get this far! If the bu;bs are formed I’d get them up. Its best to get your garlic up before the tops dry off – it stores longer this way if the top remains sealed. https://www.ediblebackyard.co.nz/how-and-when-to-harvest-garlic/.
Hi Kath,
Thanks to you for tips and everyone else for excellent conversation. It’s been wet as here in Dunedin and rust has arrived, promoting a huge learning curve. I will pull the garlic today and hope for the best, there are bulbs formed, though maybe not huge, but I will take advantage of the drier warmer weather that appears to have finally come.
wishing you all a home grown Merry Christmas, Viki
Hi kath,
I’ve tried a few things in the last couple of years since getting rust (which I’ve accepted as my patch is too small to avoid it). I’ve found that hardnecK garlic is more resistant than softneck, and growing in the greenhouse seems to mitigate the problem.
Nice one Rhys, thanks for our note. Yes I had a go in the greenhouse too and got no rust but it got too hot for the garlic by November and it really needed another month to finish off but didn’t make it. This years miserable spring would’ve probably been perfect! Charles Dowdling grows successfully in his greenhouse but then hes in England – bit colder me thinks. Growing a mixture of varieties is such good insurance – no matter what the season someone will be happy. 🙂
HI Kath, In Sth Auckland. I had rust first time last year and still got a reasonable harvest stripping back, chopping and freezing as you advised, rather than drying. I then didn’t get this years crop in till August (against all my best intentions) but doing everything as you advised and had high hopes, Unfortunately ust appeared a week ago but I take heart that the bulbs appear to be huge, so will harvest this weekend. Thanks for all that info and feedback everyone. I am getting wiser every year!
Q- I add the ash from my burnings to my compost. If I sack and burn the leaves will it survive or should I keep for the paddock bonfire?
Good to hear Tricia, thanks for letting us all know. I hope you get an early crop in this year – perhaps it’ll be your saving grace. Lok forward to hear how you get on. And if the rust can survive burning then I’ll be super impressed – I too burn and recycle. Enjoy!
hi all .Has any one got some info on how long you leave garlic on the ground before you hang it up . . . Secondly we dug our garlic over 7 days ago and have had rain since . The garlic is wet lying on ground with rain forecast for the next 3 days . it has been suggested we should cut of tops and try and dry in racks to save it from rotting . . Any help would be appreciated . We live in North Canterbury .Cheers Matthew .
Thats a shame Matthew – I bring it in right away after harvest and dry it on racks under my deck in the shade with good airflow. I’d definately get your garlic in as soon as a lay it out in a single layer on wire or baskets to dry. You could also peg it up inidiviually – depends on the size of your crop. Here are all my thoughts on harvesting garlic https://www.ediblebackyard.co.nz/how-and-when-to-harvest-garlic/ If you do trim the tops be sure to leave a stub at this curing stage so the bulb remains sealed- all the best Kath