Did covering plants work for the spring freeze? Last night, we had a hard freeze in central Oklahoma. It got down to 30° for several hours. It wasn’t 26°F, but it wasn’t good either.
Bummer. We were having such a nice springtime too.
Sometimes, I ignore my own good advice.
Because the weather was so settled for most of April, I planted a few tropical plants like petunias, coleus, and calibrochoas in my containers on the back deck. Yes, I know better, but my greenhouse was getting too full. Sometimes, I ignore my own good advice.
I hope you didn’t plant tomatoes, peppers, or eggplant transplants.
I did not plant out tomatoes, peppers, or other hot-weather-loving vegetable transplants because I know they are picky little devils. If you did plant tomatoes, just go buy more and wait until 55°F nights. Your new plants will catch up just fine. Chalk it up to a learning experience.
Tropical plants hate cold temperatures.
Tropical plants hate temperatures below 45°F. I know this. You know this. Sometimes, we still stretch our hardiness zones. By the way, 30°F on April 20 is some kind of record according to the meteorologist this morning. I don’t see how since it’s our last average frost/freeze date, but whatever.
How did the tropical plants do under their covers?
I reused plastic pots for the in-ground plants and those in raised beds. I used heavy contractor trash bags and regular black plastic trash bags on the containers.
I did not cover my perennials, shrubs, or trees. They were on their own and did just fine. Several gardener friends did cover their hostas and such. I get it. It’s scary to lose that initial growth, but my garden is too big to worry about perennials unless our temperatures go down to 26°F.
The secret to covering plants before a spring freeze.
The secret to covering plants before a spring freeze is to trap the Earth’s heat beneath your covering. Therefore, whatever covering you use should go all the way to the ground. On a raised deck, you can’t really do this. You just hope for a degree or two warmer. It’s also best if the covering doesn’t touch the leaves of the plant.
Also, water your plants before covering them. A well-watered plant will be better protected than one that is dry and tired.
Don’t cover trees like lollipops.
Covering trees like “lollipops” won’t do much if anything. Remember, you’re trying to trap the heat of the earth and raise the temperature a few degrees. You can also put Christmas lights on a special tree and cover it to the ground to raise the temperature, but unless the covering goes all the way down, it still won’t work. Also, I’m not sure if the newer, LED lights will work for this.
Here’s what I discovered once I uncovered my plants.
The nicotiana, flowering tobacco, did just fine with N. langsdorffii, being the hardiest. N. ‘Peach Screamer’ was the least hardy, and I’ve been watching them throughout the past week with rain and pretty low temperatures. We were having lows in the upper 30s for the past week. N. alata ‘Lavender Cloud was right in the hardiness middle ground. However, Stachytarpheta ‘Nectarwand Red,’ false vervain, even covered, looks like a goner. Good thing I bought three more plants at Bustani Plant Farm yesterday. I stowed these babies and others in my greenhouse.
This brings me to why I stretch the season sometimes. By the time, we reach our last freeze/frost date, my greenhouse is stuffed full. It’s always a race to get everything planted before our weather is too hot because it’s even hotter in the greenhouse. So, I sometimes push things a little, and some years, I’m running pots of tender things back into the greenhouse for one more day.
That’s what I did with the pelargoniums. They may not look like much right now, but I love these little scented plants, so Bill and I ran them in the night before last. It was quite the job.
Containers on the deck
In the containers on the deck, almost everything survived after being covered. The petunias, calibrochoas, wire vine, etc. are all ok. The coleus took the big hits, but they may come out of it too.
As for the plants in the raised beds, everything covered came through except the tithonia, and I take the blame for that. I may watch it though. Tithonia ‘Torch’ is one tough plant. We shall see in the next few days. Here’s what the bloom looks like in happier days. Since I started all of my tithonia from seeds, I’m a bit sad about it.
To cover or not to cover, that is the question.
On the question of whether to cover or not, I think covering some tender things is a good idea especially if they are near the ground or if you can cover the entire container. The best bet, however, is to wait to buy and plant tropicals after April 20. However, I want to point out we had terrible weather a few years ago on May 2, 2013 which is way past our last average freeze date. We also had a really hard freeze on April 7, 2018. That year, I did cover some newly planted perennials.
Another conflict is if you wait too long, Oklahoma may have one of those non-existent springs, and nothing will get settled before summer heat sets in.
It’s a tough call.
If you’d like to listen about happier gardening topics, this week on the Gardenangelists we talked about digging and dividing bulbs and perennials.
See you soon. Don’t worry and keep on gardening.