Green house question

dustin0352 · Post by **dustin0352** » Sun Apr 12, 2009 3:28 pm

What benifits would I gain from a green house here in Florida? I know nothing about them and what they provide for cacti. Is it just added heat for the winter time? or do they provide more light in low light areas?? There is a kit at my local nursery for $150 and it is 8x10. Would this be worth getting??

iann · Post by **iann** » Sun Apr 12, 2009 4:23 pm

It would keep the rain off

Post by **CoronaCactus** » Tue Apr 14, 2009 5:04 pm

As i've found out, it definetely helps to get the plants growing early after a winter in a GH.

I think the the thing you'll fight with most is the high humidity in Florida.

dustin0352 · Post by **dustin0352** » Tue Apr 14, 2009 11:38 pm

Yea humidity is a problems here. Wich i combat with less watering. Could put damp rid in the greenhouse... Next question is does it still need to be in direct sun?

Post by **CoronaCactus** » Wed Apr 15, 2009 1:26 am

If possible, yes.
You can always subtract sunlight with shadecloth, but it's pretty hard to add more sunlight

dustin0352 · Post by **dustin0352** » Wed Apr 15, 2009 1:32 am

Thats my problem. Have so many dagone trees in the back yard that I only have one spot that gets about 4 hours of direct sun a day. Then its in the shade it goes. The front yard is great with about 9-11 hours of direct, buts we's cant's put's no green house in the front. (I know Florida is known for redneckish things, but we's not thems folks)lol. The shade is still kinda bright shade maybe it will work, guess gotta try. Nothing like a lil trial and error.

Post by **daiv** » Wed Apr 15, 2009 1:54 am

Another advantage would come on those occasional cold nights you were worried about this last winter.

Tony · Post by **Tony** » Wed Apr 15, 2009 2:10 am

I'd start whackin trees if I was you.

If anything you could just use it to overwinter alot of plants that would otherwise be outside the rest of the year, I always jam pack mine in the winter.

Post by **daiv** » Wed Apr 15, 2009 2:52 am

Dustin,
Don't overlook the Epi cacti! You could grow a mean S. chrysocardium there I bet!

toddo · Post by **toddo** » Wed Apr 15, 2009 5:23 am

I have one here in So. Cal and while I dont need one it sure is nice to have all of your plants in a somewhat orderly spot. There's a little learning curve involved with it (at least there was for me) but once you get it dialed in (temps/fans/shade/etc.) Plants grow great in them. It's always a little warmer in there than outside (great in spring - not so great in summer). Here's a shot I took of my thermometer of the night lows during our bad freeze a couple of years ago. My garden outside and many potted plants melted at 23F but I had no losses in the greenhouse at 30F. It really saved me that night.

iann · Post by **iann** » Wed Apr 15, 2009 11:30 am

Humidity should only be a problem if you keep the greenhouse closed up. With reasonable ventilation, the increased temperature creates quite low relative humidity. In summer the humidity in my greenhouse drops so low that my thermometer can't read it. Closed up in winter it would hit 100% and stay there forever.

Even with mostly shade, a greenhouse will give you a fair bit of extra heat but it can never give you extra light. I would think that too much heat would be a problem for you nine months of the year. With direct sun, a little visible light is lost, but not enough to bother most people. Even in England many growers add shading for the summer. Greenhouse glazing does block most UV and this is a big difference from being outside. Glazing also increases the heating effect of the sun. This increases the ambient temperature inside the greenhouse but may also cause scorching problems.

Toddo's right, its a learning curve. If nothing else though, its somewhere to keep your plants. Watch out for hurricanes!

Post by **daiv** » Wed Apr 15, 2009 2:08 pm

iann wrote: Greenhouse glazing does block most UV and this is a big difference from being outside.

We talked about this a little when discussing artificial lights including Reptile UV bulbs. Ian, if anyone would know, you would. Does the UV help produce more dense spines than on plants without it? Any known benefits or drawbacks to UV on cacti?

iann · Post by **iann** » Wed Apr 15, 2009 2:31 pm

UV is a stress on plants and it induces responses to deal with that stress. In cacti these include wool and hair, denser spines, skin pigments, also potentially powdery skin blooms and waxes. In species not sufficiently able to deal with the level of UV though genetic inability or insufficient adaptation, UV produces bleaching by destruction of chlorophyll and eventually death of cells near the surface of the plant.

A response which may not be directly attributed to the UV, but could just be a general response to short wavelength radiation including blue visible light, is more compact plants.

peterb · Post by **peterb** » Wed Apr 15, 2009 2:35 pm

I thought special "plastics" for greenhouse coverings let in UV?

peterb

Post by **CoronaCactus** » Wed Apr 15, 2009 3:03 pm

I heard the same. The polycarbonate sheets allow the UV to pass through, actual glass does not.