Heated planter/greenhouse idea.

I would like to get some opinions on an idea I have.
I want to convert one of my planters I built into a small greenhouse that I can have my seedlings in while growing.
I have a heated cord used for keeping ice build up off the roof edge of the house. It is low wattage, so shouldn't use much power.




I would bury that cord in the dirt in the planter and then have this lid on it. It should gradually heat up the soil and the whole planter. I may even be able to start some plants early in that soil.




I could make the lid sloped for water run off. What do you all think of this idea?

 

Sounds good, basically an outdoor propagator but you will be planting directly into it.

Might need some experiment to see how much heat the cable will give you and you could either use a thermostat or put it on a timer just for overnight use.

 

Many low wattage heaters don't have thermostats but I'd of thought that if using for bottom heat you'd need to regulate the heat? Low heat in a large area might not need regulation but would in small propagator. Hope the wattage not likely to leak?

 

@harrylee your set up looks interesting. How early were you hoping to start and what type of plants are wanting to start early?

 

Looks like I am dead in the water right now on this, heater won't work above freezing it seems. Will have to look at a different type of heat source.

 

It all depends on what you want to start early and when. I have had cold frames in the past and just recently dismantled them because I simply threw my hands in the air and started planting perennials in those beds. For my annuals which I mostly grow from seed, I keep them inside until mid April and that is when I move them into the greenhouse which is heated with a small natural gas heater. The heater is kept on only enough to keep the temperature above freezing at night. To heat it higher or earlier would cost a fortune!

Even inside, because a lot of seedlings are in the cellar under lights, I have those heat mats with thermostats. Now, one of those might work in your set up? Although it would definitely be running 24/7 in the winter I would think?

 

I was assuming it was similar to a soil warming cable the type we use for making propagators.
You then just add a separate thermostat which switches it on and off.
The type of cable you are using is not that common over here, but I have heard of people using something similar to stop tender plants freezing on cold nights.