Greenhouse fruit update
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!