Cold soil

Stick to a 650 to 750ppm feed, get 10-15% runoff waste water every time you irrigate -- wait for top 1" to dry before repeating. I'd treat it like a soilless grow if you are using 'hydro' nutes. Depending on how hot the soil is, you may want to delay and ramp up to this level of feed. check my diaries for some ballpark PPMs of N/P/K/Ca/Mg/S - your tap water may impact those last three. i hve hard water, you may need more of those if you have water with fewer solutes already in it. cold is probably from evaporation, which is an endothermic reaction. As long as the ground it rests on isn't abnormally cold, you probably don't have to worry too much about this. The pot will always be cooler than sorroundings due to constant evaporation. Same concept behind evaporative coolers. Anyway, as long as you stick with that 10% runoff or more, the pH and nutrient concentrations will remain in a healthy, happy range. if you like this method of growing, gets some pet-based or coco-based substrate. Go 50/50 with perlite + peat base or 70/30 coco/perlite. Dont buy 'raw' sphagnum peat... nor a brick of coco, as both require additional processing. Something like Promix HP or BX is good or any respectful coco brand... avoid the bricks, i can't say it enough, lol. ppl love coco around here, but sphagnum peat is better, imo.. lower resting EC, no additional buffering of nutes due to excess K+ ions in coco or even Na+, since the shit grows on a beach next to oceans, lol. Coco is better for environment? BWAHAH not if you consider all the water and chemicals it takes to process the shit to make it useable, lol.... but really, if you use either you will never know the difference in a small garden... unless you get a shitty batch of coco and nearly kill some plants with salinity issues.

Henlo my friend. Erm how cold is too cold anyway of sticking a thermoniter in there ? Anyway I would try and water with water between 20-24c this will not harm your plants and it will heat up the medium it will also help her eat through them sythetic nutes abit better thats why its best to flush plants with warmer water. People who use cold and ice are trying to increase the terps but its not proven extra darkness at the end of a flower cycle has been proven to increase alot though from thc to terp profile ect. anyway other than that you can keep a little fan heater somewhere and connect it to a timer to come on once a day or something though if this is outdoors in a pot I think the best thing to do would be try find a place where the cold air cant get to it as much but the sun still can so like infront of a north facing wall for example there are many ways to heat up an outdoor plant though this time of year temps will be getting colder so you may struggle in the coming months though best of luck anyway :)