May is when many people think of planting their garden, and when I say planting I mean annuals 🙂 Now, maybe you’re like me, and have already been moving, dividing and planting the hardy stuff for a few weeks in between the rains, but when it comes to plants that you have started indoors or purchased from a greenhouse, there’s an important TLC step, called hardening off.  They’ve been living a sheltered life indoors and need an adjustment period before setting them free to be planted in the great outdoors.
Thoughtful plant care is the intention behind hardening off, whether your plants are hardy or tender, and will prevent a few of the following, awful things from happening to your indoor grown plants:Â Â
- Sunlight is far brighter than anything indoors, including grow lights, and plants can actually get sunburn, which shows up as bleached areas on the foliage.Â
- Wind can dry out soil quickly in small containers, and can also stress or damage foliage.
- Cold temperatures can cause blackened foliage and droopy stems.Â
- Planting in cold soil can stunt heat loving plants, setting them back a few weeks and invite in rot and mold…or worse.
Hardening off can get complicated, with rules to follow about leaving plants out longer each day and increasing sun exposure each time, but when I started gardening I had a life (I’m sure you can relate) and didn’t have a week to be messing around with all that. So I did what my garden mentor taught me (my Mom, who is an amazing and accomplished gardener, thanks Mom!) and so now you know this method is Mom approved. Happy Mother’s Day!
For tender annuals, about a week before our last average frost date of May 15th is the right timing for this. You can also watch the forecast and see when the night temperatures are pretty reliably above 50 degrees. Remember, the average last frost date is an average to consider it safe to plant, and is not set in stone. Some people use Mother’s Day or even wait until Memorial Day as their planting date for annuals, that’s completely up to you.Â
If you’ve purchased hardy plants or cool season annuals you can start this process any time after the middle of April, watching nighttime temps above 40 for the cool season annuals, to start, hardy perennials, etc. can handle cooler temps but mid 30’s to start are pretty safe.
The first couple days, put plants outside for a few hours in a full shade spot that is protected from the wind. If you plan it right, you can do this on the weekend if you work, but a few hours in the evening is fine too. Bring them inside at night.
Next step is leaving the plants outside all day for a day or two, again in that full shade spot that is protected from the wind, still bringing them inside at night. After that, if nighttime temps are above 50 degrees, you can leave them outside all night (60 for heat lovers like basil, peppers, lantana, etc).
Pro Tip:Â Your plants may dry out much faster than they did indoors, especially if they’re in small containers or are rootbound, and may need to be watered in both the morning and evening.
Pro Tip: Just in case, watch the forecast and be prepared to cover if temps dip. This has been an unpredictable spring, as per usual, and we could get a chilly night or two, even later in May