Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

Are there any guidelines for temperatures for best growth in greenhouses?  It's only mid March here in central California and the temp in the greenhouse was 106 degrees.  It's a 16X16X12 foot greenhouse.  Any ideas for cooling it down would be appreciated  Thank you... 

Views: 381

Reply to This

Replies to This Discussion

It looks like most common vegetables except lettuce/spinach types would tolerate 90F... some even 100F.  There is a lot of useful info here: http://cmg.colostate.edu/gardennotes/720.pdf

I think most greenhouses around here use "shade cloth" to keep some of the sun/heat out in the first place... your vegetables can only use about 30% - 40% of the light from "direct" sunlight; so 70% cloth would go a long way without harming your growth rates.

Vent the excess heat out... either "passive" vents or "powered" fans in vents; on thermostats if possible.

Hi Nancy,

We came back from town the other day and found the GH (20 x 24) had reached 112F real temp (versus t-stat sitting in direct sun:-) and everything was fine due to the constant watering I would guess. Lettuce looked fine. Tomatoes were a bit giddy as we have had very few sunny days here lately (about 1 out of 5). Swiss Chard was the only veg looking a bit stressed but that too was fine within hours. Unlike a standard "dirt" GH nothing had dried out and the media has a great cooling system in AP. The AP has given me and my wife a whole new enthusiasm for gardening again. And now year round. We have gotten a bit carried away ordering and starting seeds. Even that is easier as I set the open bottom trays right in an open area in a GB (dug in a bit to reach the water) and the start ups get watered on auto pilot as well.

Needless to say, having just finished automating the wood stove, I am now focused on automatic powered vents

Here in the mountains the temp swings can be very dramatic. Makes things a bit more challenging but the Summers are outstanding.

Thanks David,   I checked out the website it had some good useful information.  The shade cloth is a great idea. Thanks again for your help.

David - WI said:

It looks like most common vegetables except lettuce/spinach types would tolerate 90F... some even 100F.  There is a lot of useful info here: http://cmg.colostate.edu/gardennotes/720.pdf

I think most greenhouses around here use "shade cloth" to keep some of the sun/heat out in the first place... your vegetables can only use about 30% - 40% of the light from "direct" sunlight; so 70% cloth would go a long way without harming your growth rates.

Vent the excess heat out... either "passive" vents or "powered" fans in vents; on thermostats if possible.

Hi Jim, Thanks for the encouragement.  I must say everything perked back up when the temp dropped like nothing ever happened.  


Jim Fisk said:

Hi Nancy,

We came back from town the other day and found the GH (20 x 24) had reached 112F real temp (versus t-stat sitting in direct sun:-) and everything was fine due to the constant watering I would guess. Lettuce looked fine. Tomatoes were a bit giddy as we have had very few sunny days here lately (about 1 out of 5). Swiss Chard was the only veg looking a bit stressed but that too was fine within hours. Unlike a standard "dirt" GH nothing had dried out and the media has a great cooling system in AP. The AP has given me and my wife a whole new enthusiasm for gardening again. And now year round. We have gotten a bit carried away ordering and starting seeds. Even that is easier as I set the open bottom trays right in an open area in a GB (dug in a bit to reach the water) and the start ups get watered on auto pilot as well.

Needless to say, having just finished automating the wood stove, I am now focused on automatic powered vents

Here in the mountains the temp swings can be very dramatic. Makes things a bit more challenging but the Summers are outstanding.

Have to see how they taste.  Supposedly the cellular damage from heat stress is not "reversible"... but I don't know for sure; only what I've read.

As Jim said, having virtually "unlimited" access to water would help the plants transpire (sweat) to stay cooler without running out of water like they would in soil that was hot & relatively dry.

Hey David, depends upon degree I'm sure. In my case the Swiss Chard was just not it's usual perky self. If it had been in the garden at those temps I bet it wouldn't have looked so good and might not have come back at all. But I know what you mean.

David - WI said:

Have to see how they taste.  Supposedly the cellular damage from heat stress is not "reversible"... but I don't know for sure; only what I've read.

As Jim said, having virtually "unlimited" access to water would help the plants transpire (sweat) to stay cooler without running out of water like they would in soil that was hot & relatively dry.

This is a tough time of year for regulating temps in a greenhouse here in north Louisiana. It gets cold enough at night that my heaters kick on., but once the sun hits it, it heats up to over 100. I can;t use the vents or leave the door open all the time like I do in summer.

That being said, my seedlings are doing great. I just have to keep them watered. My main seedlings in there are tomatoes and peppers- a few hundred of each.

Later, when temps are consistently hot and I want to keep some plants growing inside, i will open the vents and door for good air flow and run a mister. You find these misters sold in the bigbox stores to keep patios cool etc  Now these plants are all in soil...My aquaponic beds are all outside so I will have to see where the water temps go.

You guys might want to try and cool it down a little :) Temps in the 100's aren't really good for much anything. Even sub-tropical types like tomatoes will drop flowers at much above the mid 90's. 106 to 112...wow, that seems like a transpiration nightmare 

I'm not saying that many plants (particularly if their roots are submerged in water) wont survive a couple bouts...but sheesh, those kind of repeated/sustained fluctuation highs are pretty stressful to be sure. Just my 2cents...

Vlad, I agree. this time of year is particularly stressful for seedlings. Here it is part of keeping the greenhouse going. after reading and posting earlier i went out and water  2 tubs of plants that were stressed. The others were unscathed. I removed my thermometer a few days ago to monitor another system but I could tell the temp was VERY high. I could not have withstood the temps inside for  any extended time.

The temp of the  water starts at about 68 degrees in the am and goes up to about 72, I suppose that helps. I've got a fan going with both intake vents and another fan pushing hot air out. I can't say about tasting   the veggies (swiss chard) yet. I'll probably try them some time next week. The greenhouse didn't get as hot today around 95 degrees.  Think I'm going to put up shade cloth. The outside temp at it's high is  around 75.  I planted some sweet basil and onions this morning, this evening they look great.  YUM!

David - WI said:

Have to see how they taste.  Supposedly the cellular damage from heat stress is not "reversible"... but I don't know for sure; only what I've read.

As Jim said, having virtually "unlimited" access to water would help the plants transpire (sweat) to stay cooler without running out of water like they would in soil that was hot & relatively dry.

Reply to Discussion

RSS

© 2020   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service