DIY Indoor Greenhouse

Spring time is just around the corner and I wanted to get ahead of the curve this year. Instead of buying flowers, vegetables, and other living things from local nurseries I will be growing everything from seed. After some quick online searching, kits for sale range from $600 to $1000!! So, in a recurring theme, I will be taking the (much) DIY approach!

A simple power strip timer controls the lights and heat mats. The controller I picked up has four outlets that are operated by the timer and four that are powered by the power switch. This worked out well because the heat mats needs to always be on, while the lights need to by cycled.


The hardware store had some handy greenhouse kits to get the plants growing. I found some cheap condensed seedling soil (just add water, woo woo woo!). I found it’s mainly made out of coconut fiber, the same fiber I mix with sand for my crabitat (and a lot cheaper!). I needed two bricks to cover the four flats.

The shelving I chose ended up being a little too short. Each of the flats sticks out a few inches off of the shelf. I will need to come up with a solution for keeping the heating mats pressed against the flats.

The heating mats seem to be pretty standard across various brands. They all have green writing and similar diagrams on them. My local hardware store had them for a few dollars cheaper than online.


Each of the lamps are held on via nuts and bolts attached to the shelving. The chains can be adjusted to change the height of the lamps. After the plants emerge from the ground the lamps can be lowered to a few inches off of the bed and then raised up as the plants get larger. There is an additional shelf that can still be attached, but I do not need it right now. Each lamp has both a cool white and soft white bulbs to help cover the light spectrum. The online community doesn’t see this solution as efficient as purpose-made grow lights, but my local hardware store was out of stock. I’ve read mixed findings on what the best bulbs to use are anyway, so I stuck with the cheapest available and got two different temperatures, even though it might not have any tangible results.


I’ve started with some flowers, tomatoes, and green beans. With 4 flats, I can start 288 seedlings at the same time. LOTS of flowers!

In the future the current shelving can accommodate the ability to double the number of flats. I don’t think my apartment’s small backyard could handle that much organic material in such a small place. Maybe when I move into a house :).

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