A lot of you northerners will be going through hardening off processes soon. Let’s talk about what we’re looking out for, and more specifically, what we’re trying to prevent!
Just like us humans, plants can get a sunburn. Also just like humans, a little bit of sun exposure might result in a mild sunburn. But a lot of exposure can result in a bad sunburn. The goal of hardening off gradually is to help prevent this for our plants. You can literally think of hardening off like teaching your plant to build up a natural sun tan lotion.
As most of you know, a mild sunburn isn’t really a big deal. But, a severe sunburn is a very unpleasant, painful experience. It’s exactly like that for our plants, except that a severe sunburn can be lethal to our little seedlings!
What you’re looking for is your plant’s leaves turning white. This indicates that your plants are getting that sunburn. Now, as we mentioned above, a little bit isn’t going to be all that harmful. But, if this continues and you’re careless with your plants, it’s quite possible they may not survive. Once all that green is gone, the plant can no longer photosynthesize and its “game over.”
If you see this, it’s a good idea to slow down your hardening off process a little bit. The best protections come from small amounts of exposure, repeated over multiple days. We recommend no more than two hours of exposure for the first three days you’re introducing your plants to the sun!
Broad leafed plants like nasturtium, squash and cucumber will have an inherently higher risk of getting this sunburn. Whereas narrow leafed plants will typically have lower risks. You might want to adjust your hardening off process based entirely on this characteristic for this reason.
Most years, we do see a tiny bit of sunburn on some of our plants, like our image shows. This comes from the fact that our hardening off process is as short as possible. It can be longer! We’ve been doing this long enough to know that even though we see this, it’s not that big of a deal and our plants will recover. It will also be inconsequential over the long term.
So, if you see this developing on your plants, you are pushing things too fast! Slow down a bit and your plants will appreciate your care for them!
