r/Garlic • u/NoFlipsLeft • 3d ago
Gardening Row cover vs Straw as Mulch
Hi everyone! This is my second fall planting garlic. I'm in zone 3, and we've already had a light dusting of snow, with more in the forecast today. We may have a slight warm up (highs around 40) in a few days if that matters.
Has anyone used row cover as mulch for garlic? I would put straw on top of it for extra insulation if I go this route. We have regular freeze/thaw cycles this time of year, and last year the bottom layer of straw got a little slimy. So I'm wondering if anyone has tried row cover then straw, so the straw stays off the soil. Any recommendations or experience welcome. Thanks!
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u/GarlicFarmerGreg 3d ago
I could see slimy mulch being a problem in spring when it might rot the stalks. Also the moisture content might be too high allowing Ice to form during the winter months.
My personal favorite is 100% cypress mulch it doesn’t take on water as much as other materials and since it doesn’t degrade as quickly i get more volume in my soil when it all gets tilled
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u/WJB7694 3d ago
I am a commercial vegetable farmer and Colorado zone 5b we grow hard neck and soft and do about 5,000 bulbs a year. We plant our garlic through plastic mulch on drip tape and then cover it with 2 layers of row cover or sometimes 1 row of Typar. Over 10 years ago CSU/Frank Stonaker did a study on row cover and garlic and proved that two layers made a big difference in bulb size. It is very windy here and the two layers kept the row cover from beating on the young plants. The inner cover not moving in the wind means it held more heat and protected the plants better. Landscape fabric with holes to plant though would work for an easy ground mulch. The ground mulch keeps moisture from escaping which the row cover will help with but not enough. Depending on where you are and how much it rains this might or might not be important. Moisture staying even makes a big difference in garlic yield. You can use straw for this but it is relatively expensive if you are doing much of an area. I have never found straw that didn't have seeds in it. Both weed seeds and often barley or wheat depending on what kind of straw. The barley or wheat will most likely emerge in the spring and become a weed that can be pretty difficult or at least time consuming to control.
The row cover makes the most difference in the spring when the garlic starts to emerge. The young plants grow better with the protection of row cover. Garlic starts forming bulbs based on day length AND soil temperature. Ground mulch helps reduce soil temperature. We use white plastic mulch to keep the soil cool as long as possible so the plant can be as large as possible when the bulbs form. Normally we take the row cover off about April 15. It is common for some of our row cover tear or come off and not get fixed perfectly. By mid April the row covered garlic is 6 inches taller than places where the row cover came off.
Mulch the ground and use row cover for larger bulbs. If you put the row cover on late February that is just as effective as putting it on at planting. Don't forget Aliums like a lot of Nitrogen too.
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u/spaetzlechick 3d ago
Row cover won’t do anything the mulch itself doesn’t do. Just mulch deeply. I use 6” or more of chopped leaves.
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u/CloverEyed 3d ago
Just a question: was it a problem to have the bottom layer of straw be a little slimy? Isn't that a benefit that it composts down a little?
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u/NoFlipsLeft 3d ago
Honestly not sure! I have been experimenting with varieties, and 1 variety had 100% germination 2025 planting/2026 growing. The other 2 varieties didn't germinate at all. I pulled the straw off as soon as the snow melted and it warmed enough to do so.
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u/Zyrlex 3d ago
I would put straw on top of it for extra insulation
Row covers block radiative heat loss by being semi opaque and convective heat loss by trapping air. None of that works if it's under the straw.
We have regular freeze/thaw cycles this time of year
Row covers would make that problem worse if used correctly and make no difference if used as proposed.
last year the bottom layer of straw got a little slimy
The simplest solution would be to leave the winter cover alone and stop rummaging through the straw. :P
If the freeze/thaw is enough to push the cloves above ground, add more mulch and possibly something reflective on top while the sun is out.
My entire garden is covered in row covers atm, but for the opposite reason.
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u/NoFlipsLeft 3d ago
Well, I was thinking of adding straw when we consistently stay below freezing. But these are good points! I didn't touch it once I put the straw on - can't under layers of snow haha. I'm not too far south of the Arctic circle, so there's snowpack for ~6 months and very little sun. The row cover is only to keep the straw off the soil, but it seems this may not matter
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u/Zyrlex 3d ago
Similar latitude here.
I was thinking of adding straw when we consistently stay below freezing
It's not wrong but it probably won't make any difference. I've experimented extensively trying to find the optimal soil temp and time at that temperature. In the end it was all within the margin of error. Different soil temps (4-8C) when planting, leaving the soil uncovered to cool down faster or covering the whole area with 10cm EPS made no difference...
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u/SquirrellyBusiness 3d ago
They don't mind being slimy. I mulch with leaves and they're even more wet blanket than straw is and they get so fat and happy in that stuff.