Sounds like you are going to create a minature lake when it rains.

Solfire - what a COOL idea!

I'd worry about rain getting in and flooding the place -
what's the drainage like that far down.

Make sure you give some shade in the summer, and have windows that open or panels that come off..

And you'll need stairs of some kind to drop into the hole
to do work or whatever....going to use PVC pipes with a plastic covering or something more permanent for the structure????

Also, consider the need for water nearby...and who knows - even an electrical outlet, just in case you want to heat it somewhat in the winters...

Have you made any kind of drawing of this? would love to see it......

MDog

Thanks a lot Mangodog, I'm very excited. :)

Flooding was the first issue i could think of as well. Luckily, this greenhouse will be right next to a 10 foot drop-off. my thought was to line the inner perimeter with trenches about 6" wide and a foot deep and have them drain out through the back wall.

I would provide ventilation and shade if necessary and yes, there will be stairs leading into it.

I was planning on making it a permanent structure. the frame out of steel and the ribs on the ceiling would most likely be cedar. I'd like the glazing to be either tempered glass or Macrolux.

There will be rainwater catchment from the roof of this greenhouse as well as from my house and workshop roofs. I'm also having some friends help me build windmills for any needed power.

There's also going to be a modest bedroom attached. :)

I'll post pictures of drawings and progress soon.

This post was edited by Solfire73 on Mon, Feb 11, 13 at 8:51

Please do solfire!

Where in texas might this be???

woofie

The only problem I've seen with trees in raised beds/fluffy soil is the wind knocking them over, but inside a greenhouse that won't be an issue.

One of the biggest problems with greenhouses is that over time they build up a healthy population of pests and diseases - which is why greenhouse owners tend to spray a lot of chemicals. An easy way around this (in my experience) is to open the greenhouse up during the warm parts of the year and let mother nature deal with it. Closed up glass houses don't allow for this as well as plastic coated hoophouses with roll up doors and side panels.

If you want to grow tropical fruit trees you don't need to keep the greenhouse super hot and humid in zone 8b, plenty of them thrive with winter temps close to freezing. The biggest problem I've had is that citrus and guava trees like new soil almost every year - that's a lot easier to do with container growing as opposed to in-the-ground planting.

I would think that in your zone, summer cooling will be a bigger problem than winter heating. Most of my trees suffer when the temps get over 100, which can happen on a 75 degree day without major ventilation.