How do you harden your seedlings?

[prose]

Each year, I start seeds in my home in sunny windows, and they grow great. I usually start tomato, pepper, squash, and pumpkin plants indoors. I try to ease their way into becoming outdoor plants, by having them spend progressively longer and longer amounts of time outside before planting them in the garden outside. Each year, the plants fry up in the sun. I end up starting more seeds in the garden at this point, and those plants do okay, but I would like to start earlier. What suggestions do you have for hardening seedling plants to the elements before planting them outside?

 

[Corzhens]

I understand about that frying in the sun because I had 3 plants that seemed to have been fried by the heat of the scorching sun. But those are flowering plants and vegetables. Tomatoes are okay in summer and they can withstand the heat of the sun provided they are irrigated in the early morning otherwise the plant might be dehydrated. About hardening the seedlings, I guess you have to plant it in the late afternoon so it can acclimatize before the sun heats up the surroundings.

 

[JBtheExplorer]

It depends a lot on temperatures and amount of sunlight.

Under average late-April, early-May conditions, I do a 10 day method that I created myself based on trial and error. I water them right before I put them outside to prevent the soil from drying up on warmer, sunnier days.

Day 1 & 2 - 30 minutes
Day 3 & 4 - 45 minutes
Day 5 & 6 - 1 hour
Day 7 - 1 hour, 15 minutes
Day 8 - 1 hour, 30 minutes
Day 9 - 1 hour 45 minutes
Day 10 - 2 hours

If they look good after two hours on day 10, I plant them that evening after the sun is down. If they look even a little weak, I'll put them out again the following day for another two hours, and repeat until they can handle it. Once they're planted, I make sure to water them every evening, at least for the first couple of weeks. I usually forget after that, but we generally have enough rain that time of year to keep them going.

When setting them out, I make some adjustments depending on the weather. If the days are cloudy, I sometimes add an extra 15 minutes if the seedlings look ok. If the days are a little warm and the plants look weak, I bring them in 15 minutes early, or put them in shade for the last 15 minutes. It all depends on how they look and what I feel like I should do.


As far as wind, some people use fans indoors to prepare them for the wind. I don't, but they sometimes need help standing.

 

[Chuck]

Once I move mine outdoors, usually when they have their first set of true leaves, I give them morning sun only and if during this time they start to look wilted I just throw a shade cloth over them. I have them in an area that is shady in the afternoon. When they get their 3rd set of true leaves I move them into full sun. If at any time the weather is going to get too cold I just move them back inside. I don't like for my seedlings to go through large temperature changes so moving them back and forth does become a PITA but after they have 5 or 6 sets of leaves they are ready to survive any temps except for when it is going to frost or freeze. I live in an area where the last frost is supposed to be mid March which is why I planted my tomatoes and pepper seeds yesterday and by planting time they're normally already starting to show buds