Which concerns are "most concerning"? Let's back up a minute and discuss the role of domes in growing seedlings indoors. First, most experienced growers don't use them at all so domes sure aren't required for any reason. Rather they are a "crutch", a tool developed for newbies and inexperienced growers to make it easier for them to maintain the soil moisture levels until the seeds germinate. Once germination happens in the tray, the standard recommendation is to remove them and leave them off. This is because the prevent adequate air circulation, trap stagnant air inside, and don't allow for proper moisture evaporation. That is the perfect recipe for damp-off, a fungus disease that attacks and kills seedlings. This is all discussed in much more detail in the FAQS on the Growing from Seed forum here. But manufacturers market them to make more money and mislead the public by showing pictures of plants growing under them. They make it appear they are required when they aren't and when the potential harm from putting them on plants indoors far outweighs any possible benefits. Some even go so far as to call them "mini-greenhouses" when there is no comparison as any GH grower can tell you. So, that said, there is no recommended role for dome covers when growing seedlings indoors once germination has happened and the risks associated with using them are several. In addition to the damp-off, there is heat buildup which can kill the plants and trapped moisture which can lead to root rot and attracts insects such as fungus gnats and spider mites, stagnant air when fresh air is required, and reduced light exposure. Your problems are not going to be solved by leaving a dome on your plants. You have left them under a dome since February and all that has done is stunt their growth and caused roots to rot. Plus you are using incandescent lights which produce lots of heat but very little light that is useable by the plants no matter how long you leave them on. Only cool white fluorescent bulbs are used in growing. seedlings and the standard recommendation for them is 16 hours on although 24 hours causes no harm. Again, all of this is discussed in great detail in the FAQs and many discussions over on the Growing from Seed forum here. Wheter you can harden them off or not I can't say. That is done outside, not inside so is a totally different discussion. But no, you cannot take them from growing indoors directly out into the direct sun. Dave

Bellaroo, I have a pond in my greenhouse and I have been using the water to water my plants and intend to continue with using the pond water. If you have fish in your pond it makes for healthy plants as they are getting fertilizer too. Using the pond water will allow me to continually perform 30% weekly water changes to keep my fish healthy. I was not going to respond to all the additional posts as this is a rather old post. However, I have noticed a few things with my pond and thought they may be useful for anyone just beginning the planning stages for a greenhouse and perhaps an indoor pond. 1. I had only 15 to 30% humidity in my greenhouse prior to adding the water in my pond. Please note where I live. It is very dry here and we very seldom have much humdity. It has increased my humidity to a very high rate 60's and 70% humidity sometimes even higher requiring me to turn on my exhaust fans. 2. If you have a wooden structure (as I do) think twice about a pond OR make sure you are using a very good primer and outdoor high gloss paint. I am flabbergasted at the amount of moisture that just drips off the polycarbonate panels I've framed into the ceiling, not to mention the moisture which drips from the walls. 3. I had initially thought the water in my gh would heat up drastically from the sun during the day and produce an abundance of heat during the evening. Not so, perhaps it's the depth of water I have. My pond is 4' deep to house my Koi for the winter months. The water has never really heated up and I can't see an enormous amount of heat that the pond is giving off into my greenhouse. 4. I tried building my pond so that I would not waste a lot of space in my gh. I built it so that if I run out of room I could build a table or plant shelves over the top of my pond allowing me to use all the space I'm using in other parts of my gh except the floor directly under the table/plant racks over my pond. Just a little food for thought when considering a pond in your greenhouse. Honestly, I love mine and hope to keep it. However, if it causes damage to my structure, I will fill it in, or just not fill it with water for one year to see if that makes a difference. Happy Greenhousing Everyone! ~Tj~

I still think the only way this would work (aside from having the hot tub in the green house, would be to capture lost heat. Now my hot tub is very well insulated, especialy above the tub. My hot tub is a self contained tub, the heater is contained in the tub enclosure. But I think this method would work even better with an inground hot tub. Idealy, if the hot tub is not installed yet, you could build an inground hot tub (the heater is seperate with an inground hot tub). Install the just the heater inside the greenhouse. Otherwise, the place I have found the most Waste heat with my Tub, is above the heater. So hputting some sort of heat exchanger above the heater to capture the heat lost from the heater would work very well.

babyboomer: Then go with a small electric heater and small fan to keep the air moving and prevent hot and cold spots. Since you're there all day, you can keep checking the temps and open the windows manually to regulate the temps. An indoor-outdoor thermometer would be helpful. How did your plants burn up with all the windows open? You kind of lost me there. Wont it happen again unless someone gets out there to open the windows in the future or have you rigged up auto-vents? I'd hate to see you lose your beloved plants again.