Soil warming newly repotted trees

[dacoontz]

So is there an ideal soil temp to be shooting for in the days following a repot? At what degrees does it then become harmful or is that not a thing. I’m not talking tropicais but more typical deciduous and coniferous species grown in the Northern half of the US. I know they each have their own preferences as well. I have a wisteria, flowering quince, stewartia, and a boulevard cypress that all needed repotting this last week or so. Temps were getting into the high 60’s but are going to drop this next week into the teens at night. I’ve bought some heating mats with a thermostat that I can stick into the soil to monitor. Looking for a little guidance for optimal goal temperature to not only protect the trees, but help them thrive.

 

[Dav4]

So is there an ideal soil temp to be shooting for in the days following a repot? At what degrees does it then become harmful or is that not a thing. I’m not talking tropicais but more typical deciduous and coniferous species grown in the Northern half of the US. I know they each have their own preferences as well. I have a wisteria, flowering quince, stewartia, and a boulevard cypress that all needed repotting this last week or so. Temps were getting into the high 60’s but are going to drop this next week into the teens at night. I’ve bought some heating mats with a thermostat that I can stick into the soil to monitor. Looking for a little guidance for optimal goal temperature to not only protect the trees, but help them thrive.

Roots become active when soil temps approach 40 F. For recently, re-potted trees, I'd set your heat mats between 40-45 F.

 

[dacoontz]

Roots become active when soil temps approach 40 F. For recently, re-potted trees, I'd set your heat mats between 40-45 F.

So goal is a soil temp between 40-45 correct. I think the mats I’m using need to be set around 75 degrees to achieve this. Still experimenting with this and finding out what the best insulating material beneath the mats will be.

 

[Deep Sea Diver]

Definitely like your set up, especially the wire mesh backbone as an effort to spread the heat.

Would recommend using a temperature controller for the heat cable though. There are various types. I like the digital ones the best. In the cold greenhouses I just use an inexpensive BriskHeat THERMO-CUBE Thermostatically Controlled Power Outlet, On at 35F / Off at 45F for the space heater. It would work for your application if all you desired to do was to keep the roots from freezing. We used these on the water trough on the farm with a submersible water heater. Never seen one burn out... but I'm sure it has happened.

We've been using 6 regular IP67 Hydrofarm heating mats for the past three years growing azalea whips from cuttings. They get soaked often, have never failed for me. No issues so far.

In our cold greenhouses commercial Hydrofarm heating mats with Inkbird temperature controllers (better temperature range) are used after early repotting, but after the chilling hour requirements are met for dormancy. The trees are kept in the cold greenhouse afterwards. I bring the temperatures up slowly from the ambient soil temperature, 35-45F, into the mid 60's over a month or so. Turns out to be about a degree F every day... or so. Nothing rigid about the schedule.

A similar process is used where I volunteer for early repots.

Ryan Neil explains how to make an outside winter round set up, including insulation in the BSOP Winter stream. It on YouTube. One can use his method for a year... (I think at 75F) if the temperatures keep the trees out of dormancy for an entire winter. Dunno how he p

That said, if the trees are kept below about... an effective 45F and above 32F they will still be in dormancy... unless you have some odd species. I see no reason, however, if the trees are keep at these temperatures to satisfy the full chilling unit requirement for that species, then repotted and raised to higher temperatures that bring the trees out of dormancy 'early'. It will take 1-2 weeks to bring most tree(s) out of dormancy. Both the roots and buds will respond.... but not necessarily simultaneously.

Looking forward to seeing your future posts.

cheers
DSD sends