Today it’s 82F outside with a dew point of 31, last I looked. Inside the GH I’m holding 58 using shade and a wet wall. Last night the low was 40. That’s pretty good chilling, 12+ Utah hours. I’ve already gotten 110 hours since Oct 28 at noon when the first cold of the fall arrived.
The goal is 700+. I could do that by mid Dec if I really pushed it. I’ll probably not push too hard and go until Jan 1. Pushing it hard would be running fans and the wet wall all night during warm spells like this. It will turn cold again late next week. That will be my chance to pile up easy hours.
At night in cold weather the heater cycles between 37-40F. That the low end of optimum chilling temperatures. Our winter averages are 60/30, day/night. So plenty of nights cold enough for max chill by using the heater to limit the low end. Below 32-34 most literature says there’s little to no chilling going on.
Everything is happy so far except my potted banana. Cold roots don’t supply enough water.
Dew point is as important as temperature when working with a wet wall. In summer where 90F inside is easily tolerable a dew point below 65 makes the wet wall effective. Above 75 dew point reduces wet wall to a humid mess. Below 50F the wet wall is very effective.
For chilling below 30 dew point is very effective even when it’s warm outside. Above 40 dew point the wet wall won’t help much. Below 20F dew point makes for very effective chilling.
The same thing could be done outside with low dew points both to get chilling or to delay bloom in spring. A misting system would do the job outside. Shade helps to keep the buds cool.
Cloudy rainy weather is good chilling weather with temps in the 30s or 40s.
I don’t have sensors that record anything. What I do have is an excellent controller with a temperature sensor. It tracks the last 24 hours high and low. And I do have a sensor to measure air temperature anytime/anywhere I want. Greenhouse temperature is top of mind every day esp during chill cycle.
The most important aspect of a high functioning greenhouse is heating and cooling, nothing else. The heating and cooling need to be dependable, adequate for all conditions, and well controlled. I just installed a backup heater. Mine failed last winter which caused the first freeze damage in 20 years. Hopefully that won’t happen again.
They both run on natural gas. Either one will hold 50F higher than outside if it runs continuously. We don’t drop below zero outside so no freezes inside if the heater is functioning correctly.
Here we are after 7 weeks on chill cycle. About 5 weeks were good chilling. So maybe 700+ chill hours. That should be enough for all the stonefruit. The mango and banana look worse than I had hoped or expected. But I think they’ll recover.
Most days during chilling the low was 37-44 and high 48-65. It will now be 42 lowest and 60s for highs gradually warming up into next month. By mid January it will be 80s and low 90s for highs with bloom starting.
This is what it looks like now. Lots of leaves to clean up and lots of fig cuttings to take. The bumblebees will have some flowers to work in addition to fruit blossoms.
Yes, almost all stay inside all year long. I’m trying to get more things in ground. Or grafted onto in ground so I can get rid of the pots. But that’s probably wishful thinking.
Tomorrow the shade tent comes down and I can start cleaning up. Then I’ll spray everything with hort oil. After that take fig cuttings for my daughter to grow out fig plants for sale.
