I just got some seedless watermelon seeds from Johnny's seeds, and I'm having a tough time getting my soil temperature above 85°F as recommended for germination. I've got them set up on a heat mat, but the best I can manage is around 75°F, and I can't keep the heat mat on all the time. As a last resort, I've even placed them under my tortoise's heat lamp! I've been brainstorming other heating methods, like putting them near a construction spotlight. Any tips or tricks to help increase the soil temperature would be much appreciated—I really want these to thrive!
3 Answers
Most budget heat mats can only raise temps by about 20 degrees. You could try moving them to a warmer room or invest in a heat mat with adjustable controls. I've also heard that putting foil over the mat can help boost the temperature a bit, though I haven't tried it myself!
Have you thought about covering the container with something? It might help trap heat. Also, consider the temperature of the water you’re using to mist the soil. If it’s cold, that could be pulling down your soil temp too. You can warm the water a bit in the microwave before using it to maintain warmth.
Hey there! Just to clarify, is the 85°F the minimum you need for sprouting, or is it just the ideal temp for growth? From my experience, 70-75°F is often fine for germination. But if the info you got says otherwise, that’s something to consider! You might have better luck in maintaining warmth with a few adjustments.
Yeah, that sounds pretty restrictive! Maybe you need a better heat source.
I know! The sheet says they won’t grow unless it’s at least 85°F. It just doesn’t seem like my heat mat is cutting it!