Warm crops in hoop houses?

How warm do nights need to be before I can put my little seedlings of tomatoes, cucumbers, zuccini, melons, squash, peppers, & other sundry warm crops into my hoop houses?

During the day, temps are quite balmy at times in there, but by morning it is always the same temp as outside. That means below freezing some nights. Will a chilly (though frost free) beginning hurt the future production of these warm season babies?

I would think you would need to bring the seedlings back inside. Do you have a mud room? you could keep them there at night and take them out during the nicer weather.

To keep things a few degrees above the outside temps, you need to put either a 2nd row cover over tender vegetation or a bunch of gallon milk jugs full of water, or both. That will get you a few degrees on cold nights.

But, it's still way too early for you to put tomatoes in the hoops. It's just too risky unless you take serious countermeasures like putting heating coils and whatnot inside the hoops.

I don't like nighttime temps below 40 for tomatoes and peppers....let alone getting close to freezing.

I was afraid of that. My babies are doing fine for now in my south facing bay window. I guess I'll just keep them in for a bit longer. I will plan on transplanting my tomatoes & peppers into 4 inch pots soon, I think.

Do you think I should transplant zuccini, mellons, squash, & cukes as well -into larger pots, I mean? My hunch is that those things don't transplant that well and I should only bother them once with the final move outside.

Can you explain what you mean by a second row cover? In my past row gardening life, I would start tomato trasplants under milk jugs with bottom cut out. Would that - inside the hoop house - be a second cover and keep things warmer at night?

Absolutely! That's what I was going to suggest....cloches. I use 2L soda bottles with the bottoms cut out.

But, to keep in a little of the day's warmth, a milk jug (or 20), will help you hold your overnight temps. Just spread them around inside. Although, it takes awhile to save up 20 milk jugs....lol.

The floating row cover I used was another piece of 6mm plastic. At night, I just unrolled it and laid it over my veggies before I closed the hoops. I tried to do this just after my garden lost the sun to trap in as much heat as possible for the night.

I will try and find you some pictures of what my setup looked like back in February. If you don't see something in a couple days, please PM me a reminder. I have a lot of irons in the proverbial fire right now.

@BackyardBirdGardner wrote:Absolutely! That's what I was going to suggest....cloches. I use 2L soda bottles with the bottoms cut out.

But, to keep in a little of the day's warmth, a milk jug (or 20), will help you hold your overnight temps. Just spread them around inside. Although, it takes awhile to save up 20 milk jugs....lol.

The floating row cover I used was another piece of 6mm plastic. At night, I just unrolled it and laid it over my veggies before I closed the hoops. I tried to do this just after my garden lost the sun to trap in as much heat as possible for the night.

I will try and find you some pictures of what my setup looked like back in February. If you don't see something in a couple days, please PM me a reminder. I have a lot of irons in the proverbial fire right now.

OK - I feel kind of dumb for asking, what do you mean "cloches"? I don't know if that is some abreviation for something... I just don't want to miss a thing. Anyway, I'll begin saving milk jugs to use as second cover. I don't know about the water jugs... I think I'll just wait another week or 2 and see if our weather warms up.

Your floating row cover sound interesting. I'll look forward to seeing it.

Cloche, I believe, is a French term. LaFee? Bueller? Basically, it's the jug with the bottom cut out. It serves the same purpose.

I would google "floating row cover" or "cloche" both and read a couple of quick articles. That will get you up to speed really fast.

French, Huh? Usn's up here in the woods ain't got so much culture as you's guys.

I will do a search and find out what I can. Thanks!

@BackyardBirdGardner wrote:Cloche, I believe, is a French term. LaFee? Bueller? Basically, it's the jug with the bottom cut out. It serves the same purpose.

I would google "floating row cover" or "cloche" both and read a couple of quick articles. That will get you up to speed really fast.

Now I'm getting it. I have seen these row covers before, just didn't know the different terms for them.

I haven't had time to do anything different to my hoop house, but I'm very glad I haven't put out any of my warm babies... It's going to get really cold tonight! 22 degrees ! Peas, lettuce, carrots, and brocoli I hope will weather this. We'll see tomorrw.

Here is the picture I promised you...



Inside you see all the milk jugs...I guess those are the few 2L bottles I used, too. But, under there are about 18 black one gallon milk jugs. And, you can see the unrolled "2nd row." When it got really cold (below 30F), I would unfold that cover and use it to provide extra protection. I would come out the next morning before too much sun hit the hoophouse and roll that 2nd cover back up and store it in the foreground where I didn't have anything planted.

Hope that helps more.

@BackyardBirdGardner wrote:Here is the picture I promised you...



Inside you see all the milk jugs...I guess those are the few 2L bottles I used, too. But, under there are about 18 black one gallon milk jugs. And, you can see the unrolled "2nd row." When it got really cold (below 30F), I would unfold that cover and use it to provide extra protection. I would come out the next morning before too much sun hit the hoophouse and roll that 2nd cover back up and store it in the foreground where I didn't have anything planted.

Hope that helps more.

Great tip... Have you ever done something like this in the fall to extend your season? or are plants too big to share space with water bottles?

No, this is/was my first season with covers and hoops. I will certainly make adjustments, and have already been thinking about autumn extension.

Right now, I'm not worried about the jugs of water because I don't really have much proof they did much. I know they don't hurt, but space wasn't a premium, either.

Here are my thoughts on water jugs for heat retention...

- The warmer the water gets, the better it protects.
- Painting black helps give you a couple more degrees. (That was tested.)
- You need sunshine to really heat them. And, cloudy days don't do much. Consecutive cloudy days are the pits when it gets cold on the second or third night.
- To get hot enough inside the hoops to bring the temps of the water jugs up to a decent differential between water temp and air temp, you have to keep the hoops closed for a few hours. Doing this will fry plants. So, it's not that feasible to allow the hoops to get to 90+ degrees.

So, in conclusion, I don't know how much the jugs help. I couldn't prove they helped much because I didn't have enough time before I started planting to figure out a system I was confident in using.

My plan for autumn is primarily concerning utilizing the warm soil temps from summer. If I use floating rows in conjunction with lower hoops (only a couple feet high), I will likely trap more heat in overnight. Remember, the plants themselves have a lot of thermal mass. That fact along with warmer soils will likely be enough to get me a few weeks past my frost date. And, that's all I'm after.

However, when I decide to go really crazy, I will likely try Boffers heated soils in his thread.

@BackyardBirdGardner wrote:However, when I decide to go really crazy, I will likely try Boffers heated soils in his thread.

Boffer's heated soils? Sounds like I need to search for that one...

Here is the thread for Boffer's H3

@Furbalsmom wrote:Here is the thread for Boffer's H3

Thanks! That looks like quite a project! I have a long term dream to add a greenhouse onto the front of our house. Boffer's idea sounds like a great first step!