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Advice on Hardening Seedlings

Posted: Sun May 10, 2015 11:00 pm
by yarnel
Hello all,

This year is my first attempt at growing my entire garden from seedlings (store bought, saving seeds starts this year). I'm having difficulty hardening my plants. I live in West Michigan and the weather here is all over the place which makes finding days to stick plants outside very hard. My wife and I were planning on transplanting them outside this weekend but this week has little to no sun, a day that is supposed to get down in the 40s, and another that is supposed to be windy. We've put them outside whenever there's been a decent day, but they still seem weak. I put them outside a couple days ago when it was 75-80 outside and they were wilty after an hour and a half. I brought them in and they rebounded but then today I made a mistake by putting them in a room with a space heater to try and get them used to high temps. A few got wilty enough to bend all the way over midway up the stem. Some I think I can save, some are toast. I'm afraid they aren't ready to go outside yet, especially because our garden area is south facing with no shade after about 9-10am.

So, long story short, is there something I can do to harden them before this weekend, should I wait a week (they are borderline too big for the tray as it is), or is there a way to protect them outside if they start to wilt?

Sorry for the long post but we've invested a lot of time and would hate to see it go to waste. Also we started enough seeds t give plants to my parents/in-laws and a couple others so I don't want to let them down either.

Thanks in advance for the help.

(Edit: next week doesn't look that great either)

Re: Advice on Hardening Seedlings

Posted: Mon May 11, 2015 12:52 am
by imafan26
I don't have as much problems with temperature fluctuations but I do get wind and rain

Actually it is easier to harden off plants on cloudy days.

You need to gradually introduce them to the light but it should also be consistent.

You don't take them out for half a day on a nice day, then leave them inside for 5 days because the weather isn't cooperative. You end up having to start over.

Start taking them out for one hour in the morning, If they do o.k. then increase it to two hours. and keep increasing the time spent outside as long as they look o.k. If you have to leave them inside for a few days, you have to retrain them because they might not tolerate the longer times.

Re: Advice on Hardening Seedlings

Posted: Mon May 11, 2015 12:56 am
by rainbowgardener
Putting them in with the heater was, as you discovered, a very bad idea. It isn't the heat you are trying to get your plants hardened to, it is sunlight, dry air, wind. A space heater is very hot and very dry.

I expect you are babying your seedlings a little much, depending of course on seedlings of what we are talking about.

Since I work, I do hardening off more with placement than hours of sun. You want to start by putting them in a very protected location, not your full sun, no shade garden spot. I have a deck that gets mainly morning sun and on the deck is a long planting bench. When I first bring seedlings out, I put them UNDER the bench. They get no direct sun there and are protected from wind. After awhile of that they can be on top of the bench and so on. I'm sure you can figure out protected spots in your location, like house corners or whatever. Put up a card table and put them under it. After they have been out a few days, you can leave them out at night, just covering if it will be chilly (but NOT freezing).

Re: Advice on Hardening Seedlings

Posted: Mon May 11, 2015 1:40 am
by yarnel
Wow, Thanks for the info. I thought it was about exposing them to direct sunlight in increasing amounts, but I see I was off there. So instead of complaining about the weather I shoukd be happy. That makes sense thst they "start over" if they are back inside too long cuz they never seemed to be stronger.

Our house faces due north and the front porch only gets a few hours of light in the morning, I'll try that tomorrow.

Right now I have cherry tomatoes, a few variations of pepper, cucumber, brussels sprouts, broccoli, others I can't remember off hand, and some variations of flowers (including Marigold, which got it the worst from my heater blunder). Are there certain plants that are easy to harden or any that are more difficult that I should watch closer than the others?

Thanks again for the help. I'm feeling a little more hopeful now.

Re: Advice on Hardening Seedlings

Posted: Mon May 11, 2015 3:06 am
by rainbowgardener
Brussels sprouts and broccoli are extremely cold hardy and frost tolerant and probably could have been in the ground a long time ago. I'm probably a zone warmer than you, but my broccoli seedlings have been in the ground a month or more and the broccoli is starting to make heads. They are cold weather crops that don't do well once it gets hot.

It is about exposing them to direct sunlight in increasing amounts. That's why cloudy days make it easier and why I start with under the bench kind of locations. However, along with the sunlight, outdoors also has wind and sometimes drier air, both of which the plant also has to get used to. " It isn't the heat you are trying to get your plants hardened to, it is sunlight, dry air, wind."

I agree with imafan that in and out all the time doesn't help. To the extent that you can, short of freezes, you want to leave them out.