Hardening off is the term used to describe the transition period from starting your seeds in an indoor environment with relatively stable temperatures and conditions to the much more volatile conditions in the garden where they’ll mature – and hopefully thrive. The transplants need some time to get used to the outdoor environment, so, in order to do so, we try to gradually wean them off of the stable indoor conditions and help them adjust to the outdoor environment.
According to many sources, here are the ideal steps in hardening off your transplants:
- Harden off gradually. You’ll want to start the hardening off process about ten days to two weeks prior to planting day.
- Start with an hour or two of outdoor sun in a relatively sheltered location.
- Protect transplants from strong sun, wind, hard rain and cool temperatures.
- Gradually increase the number of hours of sunlight, while you simultaneously gradually reduce the amount of watering over the hardening off period.
Because I’m lazy and have a predisposed deficiency when it comes to this process, here’s the Sara Method of Hardening Off:
- Once the temperatures reach above 65 degrees, move all of the transplants outside.
- Intend to gradually increase the amount of sun time over two weeks, but often forget about the transplants until it’s time for bed, when I quickly move them all inside on our dining room table only to start the whole process over the next day, inevitably losing a few transplants to wind or sunburn.
I actually planted last week, so more to come on that. This spring has been a rough one for starting plants (at least for me) because it rained so much that it was difficult to get the plants out for any hardening off at all, let alone the proper gradual method. When I planted our transplants, they were all looking a little sad and sheepish. I’m hoping that they quickly adapt to their new homes!
Here are some more resources for the hardening off process – I would just skip the Sara Method altogether!
- Hardening off process worth the effort (from Growing for Market)
- Some tips from Norma Rossel at Johnny’s Selected Seeds (including a helpful temperature chart)
- Dummies’ article on the seed starting process
- Transplant tips and tricks from Organic Gardening magazine
Leave your tips in the comments – pretty please!