Happy New Year! We are in the coldest part of our year here in Florida, with the frostiest temperatures typically spanning January and February. Sometimes it is very mild, other times, like the first week and the middle of January 2018, it gets icy here in the Tampa area. How did your garden and yard fare the frost?
We hope you took precautions, such as using N-Sulate crop cover fabric, as we suggested on our social media feed during the frost period earlier this month. Despite our best efforts though, plants can still be affected by the cold. This article should help you figure out what cold damage looks like and how to help your plants recover.
Freeze-damaged plants usually have a distinctive look, but it can also depend on the type of plant to be able to see it. In general, any changes to a plant directly after a freeze are considered freeze damage. It can look like the leaves of the plant are wilted, yellowed, browned, or burned. Stems can be crispy and dry, or slimy and mushy with an unpleasant odor. If fruit is damaged by frost it usually looks like it has soft spots.
The spots and damage appears where the water inside the plant froze and then thawed. Water expands when it freezes. If you’ve ever overfilled a water bottle and then froze it, the bottle usually breaks! The same happens inside your plants. The expansion damages the structure of the plant or fruit in that area and it becomes damaged.
What To Do
If you think your garden has some frost damage, I recommend to observe your plants closely for changes over the next week or two after the freeze has passed. Wilted leaves and stems that don’t perk up after the first week will probably not make it. The more obvious damage is the parts completely burned by frost. You will want to remove and discard (or compost!) any of the slimy stinky kind of damage as soon as possible to encourage the recovery of the rest of the plant and keep fungus and mold at bay. The other “dry” types of damage can be left alone, as they will help protect the plant from further injury.
If the entire plant is burned down to the ground, remove all of the stem and leaves and clean up the burned debris to help prevent fungus and mold.. Many annuals will be burned completely, as they are supposed to die off when the frost comes (thus the name Annuals, as in, they have to be replaced annually).
Tropical plants are also very susceptible to freeze burn, as they are not meant to be grown in areas that get any freezing temperatures (but we do anyway, gardeners are a stubborn lot). However on tropicals, even if all the foliage is burned away, come April or May you’ll often see new shoots. Clear out the dead parts before they invite fungus or mold, but wait and see what happens before you dig up the whole root ball!
Watering the soil after the temperature has returned to above-freezing is a good idea, but only if it is not supposed to freeze again the next night. Frozen ground can steal water from plant roots, and thus from foliage.
Water from the hose will be warmer than the ground and will help give the plant a little jump start. Offer the plants 1” of water, or give containers enough to allow water to flow freely out. Afterwards water as you would normally, and keep a close eye on your plants when you do to stay on top of changes – positive or negative.
Should I fertilize?
While I would love to say “yes” to this, I would actually discourage winter fertilizing. Fertilizer causes new above-ground growth, and frost paired with new growth is usually not a good combination. New leaves and stems are much more susceptible to cold damage than established stems. Additionally, growing new shoots now would also stress the already-stressed plant when it is trying to recover from the freeze.
I wouldn’t fertilize until you are reasonably sure that you have passed the frost window for the whole season.
Check your Frost Zone Indicator to see your approximate average dates of last frost (and please note, this is ONLY a guideline, and not meant to be foolproof!).
#ProTip: For fall/winter planting here in Florida, it is best to use a slow-release fertilizer or very nutrient-rich compost at the time of planting. Regularly fertilize or add compost up until before the first frost, stopping feeding through the frost period until the threat of freezing has passed. That way any latent nutrients in the soil during frost times will help the plant survive and recover from colder temperatures until Spring.
There’s my best advice for recovering your garden after a freeze. I hope it was helpful! Thanks, Marissa