Best garden covers for freeze protection

Oklahoma City’s latest freeze date on record is May 3. That record may not have fallen in the city last night, but if you think my garden didn’t suffer a late freeze, just look at this ice. It covered the outside of the plastic tunnels I used to protect my most tender plants.

Ice from the top of the row covers

Think it wasn’t cold here last night? This is ice from the top of some of the row covers.

As I wrote in my last post, a lot of the garden has achieved a certain hardiness and shrugged off a low of 31°F or lower. Perennials, shrubs and trees look great. However, I’d planted a lot of tropicals like tomatoes, coleus, alternanthera and tropical hibiscus ‘Haight Ashbury.’ Also, several of my tender bulbs had already broken the surface and were steadily growing. While I wasn’t worried about the cannas, I didn’t want to lose my dahlias so I covered them.

Plastic row tunnels with wire inserts make good freeze covers.

Plastic row tunnels with wire inserts are easy to cover a large area. They also don’t blow away.

I missed a section of the garden that faces the street, and it braved 40°F and below the night before and most of yesterday with the wind blowing. This showed a real test of those tropical plants hardier than others. I did cover this section last night, but I lost two of my favorite coleus that are new for 2013. Look at how sad this one is.

Under the Sea coleus not covered by the best freeze covers.

Under the sea coleus killed by the frost

Oh well, I know where they sell them so I’ll head back to Oklahoma City to buy three more. It was a pricey mistake, but I want those coleus in my garden. Some tropical plants like Ruellia elegans, Brazilian petunia, were fine at 40°. I did get them covered for the 31° low last night.

I only used row covers where I had a lot of space involved. For single plants, plastic pots are great.

I only used row covers where I had a lot of space involved. For single plants, plastic pots are great.

I didn’t intend to test freeze coverings, but I had so much to cover I used everything I had. With all freeze protection, you need be make sure of two things. First, plant material shouldn’t touch the top of the cover where it is coldest. This may not always be possible to keep from happening, but I did my best. Second, your covers need to stay in place all night. That may sound simple, but it’s not when the wind is blowing for all its worth. Most of these late freezes in prairie states occur during a storm, or right after, so wind is usually a factor. JWALT TunLcover Superior Plant Protectors like those shown in the photos stay in place because they have wires that go into the ground. They are fast to install and keep things pretty toasty. However, they are also pricey so I don’t have as many as I’d like. They are reusable and strong, but make sure you let them dry out between coverings. You don’t want smelly plastic with bacteria covering young plants.

Glass cloche covering a dahlia. It gets hot under there so remove as soon as possible.

Glass cloche covering a dahlia. It gets hot under there so remove as soon as possible.

Glass cloches also work well, but they are very expensive and break easily. They are, however, often used in magazines and books because they paint a pretty picture.

Gail from Clay and Limestone suggested I create a teepee from rebar and/or plastic stakes in my containers and then wrap this structure in tablecloths. By draping and placing containers up against each other to hold the coverings in place, I saved every plant. I also put containers against the house to absorb more heat. I discovered flannel-lined, plastic tablecloths are the best for this purpose. They hold in heat better than anything else I tried. They also didn’t blow off as easily, and their plastic covers shed rain. I forgot to take a photo of the teepees. I’m sorry, but you get the mental picture, right?

I also wound tablecloths through wire tomato cages to cover the tomatoes. I have nine tomatoes planted, and covers blew off three the first night when it was 40°F. I covered them again the next day. We’ll see what damage was done. Here, I found the Dalen HG25 25′ X 5′ Harvest Guard Row Cover performed really well, keeping everything toasty and remaining attached to the tomato cages. It looks like old-fashioned interfacing. You could go to a fabric store and see if something similar is available. It may or may not be cheaper.

Tablecloths drying in the sun. I'd already taken them off of the tomato cages. They were soaking wet from rain.

Tablecloths drying on the wood rack. I’d already taken them off of the tomato cages. They were soaking wet from rain.

I covered the remaining plants with plastic pots as you can see below. No, it’s not pretty, but your garden doesn’t know it looks like a junkyard. It’s a great way to repurpose and up-cycle all of those plastic pots you have in your garage. Here’s what I discovered about these pots. If you have the thinner one-gallon sized containers instead of the thick ones, stack two together and then place it over the plant. The extra air between the containers along with the extra thickness provide better insulation.

Plants were covered in everything I could find.

Plants were covered in everything I could find.

Whatever you use, the temperature warms up quickly with all that bright sunshine. Watch your weather forecasts. As long as the storm is blowing, keep things covered. If temperatures warm into the 50s, uncover everything. I usually watch for the mid-40s. You don’t want your plants to overheat after suffering such a trial. That’s insult to injury.

To recap, I found that large, plastic buckets–including five-gallon types–along with insulated, plastic tablecloths protect best. The plastic and wire-frame tunnels are great though for larger areas. Be sure to tuck in the ends so cold winds don’t simply blow through your tunnels.

This should be our last freeze, but at my house, I’m watching for that 40° benchmark. I will cover the other coleus and alternantheras if that happens, along with the new Senorita Blanca cleome in one container. They are too precious to replace. We’ve never had a freeze any later. However, Arkansas never had snow in May before either.

 

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I'm a writer, born and raised in Oklahoma, and an obsessive gardener who attempts to grow over 90 rose bushes, along with daylilies and other perennials. I also grow some mean tomatoes, and I'm gluten and casein intolerant, hence the gluten free blogs.

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17 comments on “Best garden covers for freeze protection

  1. PlantPostings

    Wow, you’ve sure had your share of late freezes/frosts this spring! That’s more common for us here in the north. I usually wait to plant annuals and veggies until mid- to late May just to avoid dealing with all the covers. But this year we had several freezes in April, so I did the upside-down pot trick, as you show. The plants that didn’t get covered (Daffodils) weren’t happy and didn’t bloom very well this year. It’s always a challenge, but some years more than others.

  2. Shari Zimmerman

    I also dug all the plastic tubs I could find out of my recycle, and employed those old curtains I’ve been meaning to throw away as plant blankets. Almost everything survived! I enjoyed the junk yard garden photos! It looked familiar.What a spring (Winter:”extended play version”)we’ve had!!

  3. Donna@Gardens Eye View

    Dee these are great tips…I have used cloth row covers and they help with one or 2 freezes but not day after day like last year …I like the idea of the pots too.

  4. Laura D M

    Loved the picture with all the upside down pots. I am beginning to feel that is what all Oklahoma Gardens look like in the spring.

    My husband and I have our act together we can now cover about 100 in 30 minutes, the uncovering takes longer.

    Please oh please let spring finally be here.

    1. Dee Nash

      Laura, it looks like spring has finally arrived. Hurray!

  5. Lisa at Greenbow

    Crazy weathers. It looks like you had it all under control.

  6. Rose

    Lots of great ideas here, Dee! I usually just gather up old blankets and bedspreads I save just for this reason. My garden does look a little strange the next morning, though:)

    The poor little coleus looks so sad; I hope you don’t have to worry about any more freezes.

  7. granny annie

    Will we ever be able to trust that spring will actually arrive and stay? I’m starting to wonder if we’ll have a summer.

  8. Lea

    Thanks for all the tips on protecting the plants. Cloches are very pretty, but I know they are expensive. I think I can find old flannel-backed tablecloths at yard sales. I had not thought of using empty flower pots – I have plenty of brick to put on top to hold them down.
    I bought tomato and pepper plants yesterday. Low this morning was 39F with almost 2 1/2 inches of rain in the gauge. I hope to get the plants into the garden on Monday, but in the meantime they are spendintg their nights huddled together on the porch next to the house.
    Have a great week-end!
    Lea
    Lea’s Menagerie

  9. Layanee

    Gardeners are tenacious and though it was a lot of work covering those plants, it was work well rewarded.

  10. martha

    Wow Dee. What a lot of covering! You are quite the garden trooper and that’s why your garden should be winning awards.

  11. Patrick's Garden

    Hey sweetie,
    Has the Greek Fisherman’s Union got back with you yet. I’m thinking we should meet for gyros some day soon. Thoughts?

    Admire your resolve to start early and defend your precious plants from the perils of climate change. I have a wonderful postcard of a French painting of young men covering plants with beautiful cloches. But you’re right about getting up early before the plants are cooked. But I think your potpourri of pots showed so much more character.

    Having six residents pot up my window boxes next week. Probably end up covering them up at some point the way the season is going.

    Blessings, my dear friend.

  12. Esther Montgomery

    Dealing with weather challenges in your garden can’t be fun – but this is an entertaining post – as well as being useful. The glass cloche is beautiful. So beautiful it would be worth having a few simply for the sake of having a few! Our weather is warming up now so I’m not needing to cover things – though I do have rhubarb under an ugly black bucket.

  13. Sonia

    I certainly hope it was our last freeze! Crazy…who would have thought we would be covering plants in May? Glad most of your plants were protected. I think our temp must have been right at 32 or 33 because all my “babies” survived without any cover. Those row covers look great I may need to invest in some for next year!
    Miss Bloomers

  14. Gail

    That’s an impressive amount of work Dee. I am glad that you’ve figured out a good system; while this might be your last frost/freeze, weather as we know it is changing and we shall have more weirdness. Thanks for the shout out, glad I could help.

  15. Marian St.Clair

    Feels like March in SC, but who knows, might be 90 degrees next week. Fingers crossed everything came through okay.

    1. Dee Nash

      Hey Marian, we are supposed to have beautiful weather after this weekend. You know I’ll be out there in the garden toiling away then. Some stuff died where covers blew off, but it happens. Gardening is definitely an adventure.