Growing Green: Preparing for the Great Outdoors (Tip #6)

Tip #6 is the most simple thing, I don't think I'll need more than a few paragraphs to explain. 

Today I'm talking about hardening off seedlings, which is the process of putting seedlings outside in the sun for increasing amounts of time each day. We need to give our tender plants a little tough love and prepare them for the weather they will encounter in the great outdoors, and we do it by hardening them off. Here's how to do it:

1. About a week and a half before your last frost date, put your seedlings out for an hour on a day when it is decent weather. It doesn't need to be the best weather, just not raining or with 50 mph wind gusts. Any temperature over 50 degrees will do, but if it is a cooler day I wait until the warmest part to put my plants out. 

2. Repeat that the next day. You may notice that your plants look a little worse for wear after being outside yesterday, but don't worry--it's all gonna' be okay. 

3. On the third and fourth days, up it to 2-3 hours. I do 3 as long as the plants aren't looking too stressed.

4. Keep increasing the time by 1-2 hours every day or two until they are outside all day. Back off if your plants throw a tantrum--they're telling you that they need to increase more gradually. I find that a common sense strategy works well with hardening off plants--if it was only 60 degrees on a certain day, that's not going to be overwhelming to a plant. However, if you get a freak 85 degree afternoon, you might need to bring your plants inside sooner than you would otherwise.

5. Once your plants have stayed outside all day and you've passed your last frost date, you are okay to transplant. I transplant before my plants have spent a night outside because they are more vulnerable to chill in their grow pots. The garden bed soil is nice and warm from being in the sun all day, so go ahead and transplant them at this point! 

Tips for Hardening off Seedlings:

• You can give yourself a little more time and start the process 2 weeks out if you're worried that you won't have enough days between hardening and transplanting. I do this when I see any dodgy weather days in the extended forecast. 
• For example, this year the extended forecast predicted a day with a 43 degree high, right in the middle of my hardening window. I knew that meant that by the time it got here, the actual weather could be even colder and may not be a suitable hardening off day. So I widened my window and added a few more days.
• It's very important to keep your plants watered during this process. Hardening off is already hard work, so make sure to give your plants everything else they need. Sort of like having a bottle of water with you when you go to the gym! :) Some plants dry out fast (tomatoes, peppers) while others don't seem to use water as quickly. So don't forget to check your plants daily!
• It's good to pack them in close to one another when you place them outside. This allows the plants to lean against one another as the wind blows, rather than falling over. Nursery pots knock over in even a light the wind, often causing leaves and branches to break. To keep everything supported, I place my plants in a block, like this:

And that is how you harden off seedlings before transplanting them outside! It's a super easy process but can get annoying. Each year by the time transplanting day gets here, I am so happy to not be moving trays of seedlings inside and out each day! 

Next up: I decided to hop ahead in my next post, to talk about fertilizer. Then I'll do a post on transplanting and the spacing method that I use.