Greenhouse - When to move plants outside

[SpacemannSpiff]

My plants are getting larger. I would like to move them out to a greenhouse. The greenhouse is small - wire frame with thick poly covering. I am in southern Ontario. How soon can I move them to the greenhouse. I don't want to lose my plants by moving them too soon.

 

[Phytoplankton]

If you move them outside now, they will go into flower, due to the light period. Probably waaay too cold for them outdoors right now. Heck, I'm in California and I wouldn't put them outside yet. You're probably talking late May or early June. When is the danger of freezing temps over?

 

[Bill284]

My plants are getting larger. I would like to move them out to a greenhouse. The greenhouse is small - wire frame with thick poly covering. I am in southern Ontario. How soon can I move them to the greenhouse. I don't want to lose my plants by moving them too soon.

Good morning @SpacemanSpiff hope your having a good day my friend.
Actually neighbor of sorts.
I just moved 6 hrs north of you.
I'm still waiting on the snow banks to melt.
I think your a bit early yet my friend.
When I lived in Toronto my mom always said don't put your vegetables in the garden before may 24.
But you have a greenhouse so that will help.
I'd check the weather for the next couple weeks.
You don't want night temps to be too far below zero or a greenhouse won't help.
If you can hold out end of May would be safer.
I'll check weather and see what it says.
As far as light goes, sunrise 5-6 ish sets 8 ish that's a good 14hrs of light.
So she shouldn't go into flower.
What light cycle is she on now?
Are you going to start a journal this year?
A bunch of us in Ontario are going to, you should too.

Stay safe
Bill

 

[Melville Hobbes]

I'm in the Hamilton area and @Bill284 is right. With a greenhouse you're probably only going to get a couple of weeks headstart on the rest of us.
That said, I've been putting my plants out earlier the last few years, closer to mid-May, as long as they're in pots. That way if the weather is going to take a turn for the worse I can bring them back inside. It also makes it easier to bring them in for supplemental lighting to make sure they don't try to shift into flower.
I also run my seedlings at 15/9 since that's about the hours of daylight we get at the end of May, so they'll be used to it when they go out.

 

[SpacemannSpiff]

Thanks for the replies

 

[SmokingWings]

I am in southern Ontario. How soon can I move them to the greenhouse. I don't want to lose my plants by moving them too soon.

Having a greenhouse must be nice. It is something I have wanted for years but the usual "life gets in the way".

To me, southern Ontario is that area from Windsor or Sarnia and the area above Lake Erie. If all those tomato farms in that area can be successful it means a great growing area during the summer. As long as the greenhouse can be closed off on cold nights the plants should be OK. Once they have hardened off to the usual night time temperatures it will be even better.

The weather can throw a curve every now and then until the overnight weather starts to remain safe. Example is the Windsor to Sarnia side of the border can have close to freezing temperatures until mid week. The current forecast for Easter Sunday is calling for possible snow, enough to measure tonight and tomorrow.

The biggest downside is that the plants will go into flower if they are out for several days or more if put out to early. We saw that several times in the early summer last year and occasionally the years before. While the "daylight" charts might say it is 14 hours we have to remember that the times listed are how astronomers track the exact time the sun will be at a specific point on the horizon. They are not measuring, nor concerned with, how bright the daylight actually is.

While it is 14 hours of 'daylight' the first hour at dawn and the last hour at sunset are so weak they do not help. The light available at those times is often less than what is in an average kitchen at the same time. Even less light if the sun comes up or sets when it is cloudy or a heavy cloud overcast.

Outdoor plants grown in the northern hemisphere will start to flower by mid August for this reason. Officially it is 14 hours of 'daylight' but the those hours at the start and end of the day are not usable for any practical Cannabis growing purposes. That drops our quality light down to 12 hours.

After mid May you should be safe as far as chances of really low overnight temperatures or the possibility that already sexually mature plants will start to flower.

The first link is the short wiki page titled Daylight and explains some of this. The article also has a few charts that I have come across on websites for commercial and residential lights and lighting systems.

Daylight - Wikipedia

This second link is to a thread titled "Plants flowering to early" started by a member in California last spring. He had put his plants in the ground in early April only to notice them flowering within a few weeks. He had to use electrical lights outdoor in the evening to give enough artificial light to get the hours back up over 12 so the plants could start to reveg or go back into the vegetating stage.

Plants flowering too early