Greenhouse humidity

Just asked my Paul if he'd ever heard of one and he said no. Paul grew up in Rochester, NY and has lived in this general area all his life.

I think it may be more specific to your area JBerger and not all of the north!

MollyD

I love the idea!!! I think they are very pretty. I'm gonna see if I can get one down here for my daughter's grave. I always put a Christmas tree there so she is still part of my holiday!!!

Jeri

That's a lovey idea Jeri! Maybe you can order it from JBerger ?

MollyD

That Grave Blanket term has got to be a very regional thing. I have lived in VT all my life and no one that I have mentioned it to here has ever heard of it. It is a very nice idea though.

Doug

This thread has a plethora of info, all of which I can use. Thank you all who have contributed. My GH is plastic, about 6 x 6'. I have a little thermostat heater which can also be used as a fan. Although the temp has fluctuated here, I don't seem to have a problem yet with keeping the GH /temp/humidity about right. Perhaps because the GH is so small.

I have learned a lot about germinating seeds from you, Tiger. You are quite a knowledgeable person on gardening, and you are making me a better gardener. Thanks.

Martha

thank you mwperry-that was nice of you to say. It is fun to be able to exchange ideas in here.

Yes, I agree. A very informative and downright pleasant thread to be a part of!

And now, off to check the g-house. 'Tis a balmy 71º here today (December!?). Guess your exhaust fans are running up a power bill today, Tiger (mine are!)

Happy Day to all
Shoe

Hi everyone. Back from a wild busy weekend. We had nearly 300 people in and out of here on the farm and they all had a wonderful holiday weekend with fun and food for the entire family. We cut way over 100 trees in two days and for our little farm that is alot. The local County paper did a story on the farm and that brought many out of our area people in just to see us. Many of them ended up with trees on their cars when they left.

I wanted to make a comment on the grave blankets....I purchase my bases for my graveblankets in Michigan, I lived my younger days in Lancaster county PA in the Amish Country. So for those of you up North, now you know what a grave blanket is. I know it has to be known by others, not just locals or the wholesalers would not sell the bases. In the old days before you could by the already made bases...people would take a couple of pieces of wood and some chicken wire and make them all. The two I make the most of are "candy cane" shape and the crosses. I am happy to share new things with you.

Daves Garden is great. You learn new things almost every day!

Doug

Live and learn!

MollyD

Back to the topic of gh's humidity; my makeshift gh's humidity level creeps up to 84%. One of my brug's cutting show white film of fungal attack. I sprayed the growing medium down with Deconyl and it seemed to have irradicated the fungal growth. I thought I'd share that with those of us with plants being overwintered.

Just now humidity in the GH is difficult to keep steady with our NO sun, cloudy, damp weather. I have not watered the plants in the greenhouse for two days. The humidity at one point was higher than the temp. Just now I am able to keep the temp at 69 and the humidity 42. I wish it would stay that way all day but it will not. I just keep praying all will be o.k. I need sun big time. I am seeing some yellow tone on some of the tropical leaves. The temp went down pretty far a few nights ago and I think they were too wet and got cold.

My RH yesterday at about 60F was 50%. I sprayed down the floor throughout and the RH came up to 64% with that maneuver alone. We have had an ice strorm, no sun, and I have only watered once in about 8 days.

SB

Morning Stress: This is really a difficult time for those of us who are having this gloomy weather. I too have not watered for days, but not 8. Wow. I doubt if I will water today. We are expecting another week of this...will you please stop sending it East and Send it West?????I need sunshine. Have a good day. This morning it is 45 deg. outside. In the GH 63 with 45 humidity. WAAAAA!

my GH is 66 degrees and 38%
what is desireable at 66 degrees ?

Jim,
Above 60% seems like the ideal, reading SB's post above. Her remedy is to use a spray nozzle to water the plants, that alone will help increase your humidity level.
Now for those of us that has higher than the ideal level, that provokes algea growth and fungus. It's tougher to control, has anyone tried to use de-humidifier in the green house's setting?
Kim

Jim, at 66F, RH of 63% gives you a VPD of 0.81 and RH of 72% gives you a VPD of 0.61. I would think that you would want to be somewhere in that range.

At 38% your VPD is 1.35 and that is a little too high.

SB

Stress: I have been trying to find the Calc-dewpoint-VPD sheet on Soho and it keeps coming up with no such document. Can you help me. I would love to have the information and just do not have time to keep searching. I need to be able to understand some more of this VPD and just can't seem to grasp it. Any help will be appreciated. JB

JBerger, go to the Zoho link in the top thread and just search the term "dewpoint." "Calc-dewpoint-VPD" didn't bring it up but "dewpoint" did. If no luck, dmail me. SB

O.K. Thanks

I give up! I went back into zoho and it would not let me in until I made an account. I did that then I was completely lost because the top line was home, forums, blogs, etc. and I looked under them all using dewpoint and it keeps saying Nothing there. Sorry, I do not mean to be a problem but zoho is really big to keep searching and I have to get busy here. If you can give me a more direct place to look. It was easy the first time in but this time with an account it was too much and then they bring up the blank spreadsheet which of course is not what I needed. LOL

Jberger, you have dmail.

Stress, I, too, would like to learn about VPD and how it is calculated. I googled SOHO and came up with everything but dewpoint. Can you help me too?

Martha

The link is in my first post. Goo to that ZOHO link, put "dewpoint" in the search window, and it SHOULD pop right up. If not, dmail me.

SB

link works for me, although I find that just watering the foliage in the am, and keeping the temps fairly consistent works ok too. I admire you guys that are so diligent with all these math tables etc......snore....lol just kidding! not!!!

Thanks, Stress! I found it. But it will be of no help. I need better measuring devices to use the chart. But at least you have given me an average safe zone, being over most temperature ranges, a GH humidity of 50-85%. Big help to me. Thanks.

I think the main value of the calculator is just to get a general sense of how the temp, RH, and VPD relate to one another.

A question (would you try to increase humidity
or be thankfull that you are not too humid ??

my yard has averaged 68 degrees 52% RH prior to our current cold spell *
my GH has averaged 68 degrees at 45% RH

hi temp hi RH low temp low RH
78 35 56 50
72 41 59 47
80 31 67 47
80 37 65 48
79 38 61 50
77.8 36.4 61.6 48.4 average



(lows at 32 degrees)

I assume, due to everyones silence, the answer is yes
45% RH at 65degrees is too low
and should be above 70 % RH to sucessfully grow

Hi Jim,
I guess everyone is terribly busy for the Holiday. I kept mine at 68F. and 64% humidity, though the humidity fluctuate (up and not lower), and most of my plants continue to grow happily, no mildew problem other than some minor one that was corrected.

those of you using a humidifier, does it run constantly ?

using a mister, i.e. cold water, does not last

I turned on the water and let it run for about an hour
the RH went up from 40% to 70%
the temperature went down from 77 to 71

I turned it off because it was getting into the afternoon and the plants were all wet
the RH went down from 70% to 50% in one hour
the temperature went up from 70 to 73

I turned it back on because the humidity was so low
the RH went up from 50% to 77%
the temperature went down from 68 to 60

It has now been off for 2 hours and the
the RH went down from 77% to 60%
the temperature went up from 61 to 62

It would have to be on most of the time to have a RH in the 70s

outside it is 40 degrees and 80% RH



This message was edited Dec 23, 2007 12:21 AM

Jim-forget the humidity-your plants are going to get rootrot/leaf fungus from too much water before they die from lack of humidity. These misters in the winter are not a great idea, imo

Jim, I agree with TL. The thing is that I don't know your winter climate. But here, I only run misters in the summer and then only roughly 10sec every 10 minutes, for cooling. The fogger may run continuously, but it is on a thermostat, so it will kick on and off. You can see the evaporative cooling effect in your numbers. If you need to run them to bring up your humidity, do it only intermittently, letting the plant foliage dry out in between.

SB

I'll add my perspective coming from a similar climate--I never do anything on purpose to increase the humidity in my greenhouse. My greenhouse is pretty small so every few days when I water the plants the humidity will go up temporarily, and when we get rainy weather the humidity will increase because of that, but during the dry sunny times in between the humidity stays relatively low and I have never had any problems caused by lack of humidity.

I think the initial phase when I first moved the plants indoor. The plants underwent a drastic changes of the outdoor's humidity and the more drier condition in the basement's gh, most newly formed buds on brugmansia aborted. But as they're adjusted. New buds continual forming. Yooohoooooo! The flowers hold their forms, and even seedpods are doing well.

I think it depends on what you are growing or sprouting in your GH because the Humidity I need for my seeds to sprout is much higher than what I need for my baby plants and seedlings. They are just like kids, all different individuals. So, I try and keep a happy medium and only mist when the sun is really bright which is not often in the winter. We have had so much rain and so little sun that I have done very little misting and only water when I test to be sure things are thirsty. But, in your part of the country I would guess you need to adjust your misting and watering to fit your type weather.

Jberger, I agree. To be clear, my initial post referred primarily to growing and established GH plants rather than seed starting.

May I take this opportunity to wish you all a very Merry Christmas. God Bless you all and your families.

Jay, I dont think that any of us were referring to starting seeds. When I start seeds in a few weeks, I will cover the flats with plastic after I mist them and seal in the humidity and once a day I will uncover them and mist them and recover the flats until they germinate-would that work for your seeds?

I've been looking at hygrometers, but I'm having difficulty choosing. The one I had selected had a very bad review from a user. I'd like one with a remote sensor so I can monitor from inside the house, and with a min/max function so I can log the differences. Suggestions? It doesn't have to be cheap, just accurate and dependable. If it has a temperature function, all the better - I can replace my current remote thermometer.