Mark: I cann't expain your lack of bloom last yr. But am very experienced with spring frost damage after 30 yrs trying to grow fruit in Amarillo. They have frost damage to something in the spring almost every year. When I was there it was rare to have damage before the blossoms began to open. It had to fall to about -10F in Dec-Jan to cause damage to buds not swelling. In Feb when some buds were swelling but not opened, I cann't ever remember damage even when the temp fell to near zero. But once the blossoms began to open we had losses of some kind 9 yrs out of ten. Damaging temp in that period were usually between 10 and 30F. I had Dapple Dandy in CA. It sets very heavily and I would recommend heavy thinning in the yrs when it sets a heavy crop. I wasn't impressed with it's quality, not sweet, but maybe even heavier thinning would help that. Hopefully you will have better results. Flavor Supreme on the other hand is among the best if not the very best fruit I have ever grown or tasted. Naturally, it is hard to set a crop...always seems to work that way. It is blooming in my greenhouse now and the bumblebees aren't attracted to it. So I am spending an hr a day hand pollinating it. I model my greenhouse somewhat to follow the chilling and temp found around Fresno CA. This is the stone fruit capitol of CA. But in the same area they have lots of grapes and citrus. So you can grow most fruit there. To me it seems too hot in the summer, daytime temp about like you and a little cooler at night. But about 30 days a yr over 100F. That seems too hot to me for most things and I don't think it is ideal but it works. I'm trying to stay cooler in mid summer. On the humidity question I try to keep it as low as possible. For most fruit this is best and it reduces disease pressure. In my greenhouse, where it never rains, there has been almost no diseases other than a small amount on overripe or split fruit. This is one of the big pluses of having a house that is covered all yr rather than an open roof for natural ventillation. We get frequent rainshowers in late summer. This alone will ruin much of the CA fruit like grapes, plums, pluots, and nectarines. You will have a hard time with things like Flavor Supreme when it rains. The Fruitnut

Sorry fruit, here is a post of yours from this past winter. I'll save you the typing trouble. Interesting setup, i'm jealous! "I'm starting the 3rd season of trying to grow fruit in a greenhouse. The greenhouse is 32ft by 54ft and 16ft tall. Trees are planted 6ft by 8ft and pruned to 8-9ft tall. Chilling cycle ran Nov 1 to Dec 28 2006 with about 950-1000 Utah hrs. Then I went to highs in 70s and heater set to maintain 34F min at night. Has been cold so most nights in 30s. Apricot material is starting to bloom. Am using bumblebees in a class C, small, hive. These bees are maniac pollinators so they do the job but about 50 of them are too many...they damage the bloom if left too long. So I am allowing them out of the hive only 2-3hrs every other day. Yes, I can force them into the hive with a one-way entrance. Last yrs fruit was the best I've ever grown but several problems remain. The apricot and plum material is still not blooming as well as I'd like, thou much better than last yr. I suspect the problem is excessive water stress on the trees last summer. Thought I was doing a better job watering than 2005 but my drip system plugged up late in 2006 and I didn't notice it until this winter. The drip tubing is underneath the weed barrier because the water runs too far from the point of application if applied on top the weed barrier. I've installed a new, better water controller for the drip system. I could just flood irrigate every 2-6wks but the trees are too vigorous when I do that. I may need to remove the weed barrier and plant bermuda grass to help control tree vigor. Next yr I should ease into the bloom cycle by running the first month after chilling with 60s for high temp. This might improve the bloom. But I'm in a hurry for fruit and, more importantly, want to be able to keep high temperatures down as long into the growing cycle as possible. Would like to be able to stay out of the 90s until the real summer fruit begins to mature. This relates to the other problem I'm having. That is that the nectarines, after the very earliest ones are suffering internal breakdown before the fruit fully matures. This may be because it is too hot. My temp contoller and thermometers seldom indicate temp in excess of low 90s, cooler than central Ca. But I have no other hypothesis for what is happening other than maybe the light level is too low. I have a light refective weed barrier on the soil to compensate for the roughly 50% reduction in light caused by the double poly top. Despite the problems I continue to think this project was worth the expense and trouble. I've learned a lot. And having trees in bloom and blueberries past bloom this time of yr is a big plus. The Central valleys of CA, which is what I model my greenhouse system after, have had a miserable yr with excess rain last spring and now a devastating freeze. Had I planted the same trees outside in this climate I'd have had almost no fruit in 2006. With the greenhouse I had Apricots starting Apr 15 and enough fruit to give much away all summer until the Crimson Seedless grapes ended in early Nov. Good luck to all in 2007! The Fruitnut"

I won't argue the vent/no vent case. I chose a vented Southern Burner A-1 rated at 25,000 btu and I need that much. My greenhouse is a different shape, it has about 1200 cubic ft which should be you approximate volume. We get down into the 30s quite often and sometimes into the 20s. I have 4 fans going , one of which moves air down so I get a pretty thorough mixture of hot and cold. You might be grateful for the extra capacity, and the Southern Burner comes with a thermostat that doesn't need an electric feed to work.

farminggreen: Presuming your use of the term "aquaculture" means growing fish for the table, unless you live in an area that never drops below freezing, I would have grave reservations about using aquarium heaters to raise water temps high enough to radiate sufficient heat to serve as space heaters, without heating the water to a degree that would kill the fish. Also, aquarium heaters are not really made to raise water temps much over 10 - 12 degrees above ambient air and why every Discus breeder I know has to use multiple heaters in their larger tanks, or risk having their 90 deg. loving fish keel over in winter, even with room temps in the 70s. I suppose it could be done, but you could end up spending far more on the heaters and electricity to run them than if you simply installed a space heater in your GH. So it's really a case of your expected air temps and the volume of warm but not hot enough to kill the fish water necessary to radiate enough heat to warm your GH. However, also keep in mind that regardless if baseboard, old fashoned cast iron stand ups, or underfloor- radiant heat circulates hot water or oil in a closed system. Fish need as much open surface as possible, which also accelerates both evaporation and heat loss. The cooler the ambient air in relation to the tank, the faster it will evaporate and require topping off, and the more wattage to maintain the optimum temp. for the health of the fish.