Forcing early bud break in apples

I found a research article that references increasing root zone soil temps and it’s affect on pushing bud break earlier.

Basically, warm up the soil and bud break moves significantly earlier.

Has anyone played with warming
Their root zone soil to try and get trees out of dormancy earlier and thus increase
The growing season? In my area (Alaska) I think I could get another 3-4 weeks of season if I encouraged an earlier bud break with only minimal risk of damage from a surprise late frost.

My initial thought was a solar heater, and running small ducting over the root zone and in the mulch. The air would heat in the body of the solar heater, then beg blown through the ducting via solar powered fan.



Warmer soil probably would push bud break. What you suggest should help warm the soil. A simpler approach might be to clear off the soil of mulch or anything else that would insulate the soil. Then cover the soil around the tree with clear plastic. Say an area at least as wide as the tree is tall. To really get carried away cover that at night with insulation and uncover during the day.

This is how I get melon seeds to germinate 2-3 times faster in early spring.

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I have been heating soil for 30 years. It works on vegetables much more than tree. I quit on trees except figs. Getting my figs growing by April 1st would increase my yield around 4 times. I loose 3/4 of my figs to frost.


How were/are you heating the soil, and what temp do you aim for?

hot water. very hot water before planting. covering soil with glass before planting. Unmulching in morning with a warm water feeding for a quick warm up to start the day. Cherry trees are helped the most because they need lots of growth in the first 2 months to do well. Timing is important. If I get a 2 week forecast of warm weather pre last frost I put my tomatoes, eggplant, and peppers in to get the roots establish so they sail through 2 weeks of cold early post frost and grow well when it warms up because they already have great roots. I no longer do extensive soil heatings. To much work. I just get a few early producing plants and wait for the main crop to catch up.

I have been meaning to test the opposite, will cool soil delay bud break? I’ve got an old bale of mulch hay in my veg garden- I think I’ll spread it the next opportunity at the base of one of my nect or peach trees and see if it flowers noticeably later than the tree next to it.

In most of the country, the main problem is early frosts killing flower buds. I’m skeptical my method will work because it seem so obvious and if it did, commercial growers might use insulated blankets like bubble wrap spread in early March while soil is still frozen to avoid freeze outs. A week delay could be a world of difference. The year before last that much would have saved the crop. Apples set fine, stone fruit didn’t.