How to Build a Seed Germinator With a Junk Refrigerator By Darold Gingerich Six years ago we started Cold Springs Garden Center, a small family greenhouse operation. We were like most others that start a family business we had plenty of ambition and high expectations, but not a lot of cash. We knew that in order to have plants to sell we would need to grow them and in order to grow them we would need to plant the seeds. That all seems easy enough, but in the last six years, we have had to learn an awful lot much of it in the school of hard knocks. If you own a greenhouse or raise a lot of plants and would like to learn how to start the seeds yourself, this little guide is for you. My goal is to share what I've learned and to help you be successful without making the same mistakes I did. As you look at all of the greenhouse grower magazines, you will see all of these nice ads for expensive equipment, plus all the stories on how the big guys do it. Sometimes we smaller growers almost despair and feel like we don't amount to a hill of beans since we don't have two acres under plastic with a $10,000 pot filler. Well, I want to tell you there is a lot of cash left on the table for the small guy that loves to work hard, cares about quality plants, and cares about his customers.
One of the best ways to have a nice plant is to start with a nice seedling, and you can buy them all day long. The big guys would like to make you think that they are the only ones that can do them right. WRONG! Most seeds will germinate with the right amount of heat, moisture, and light. You can grow a high quality seedling yourself if you have the right fancy equipment like a $4,000 germination chamber. Or for under $400 you can make one yourself like I did, and it will work even better then the fancy toys.
My first try was to use an old dishwasher. I mounted some old refrigerator racks in the top and hooked the heating element in the bottom to a thermostat, filled the bottom with water, and it worked great. I set my thermostat on 78 degrees. I think that first one held maybe 10 of the 288 trays. (The 288 seed trays are 11 inch x 22 inch and two fit side by side in the dishwasher.) Within 3-4 days my first tomatoes were sprouting all over the tray! And on the fifth day here come the peppers! Wow was I ever excited! I pulled them out and set them on a sunny bench in the greenhouse and within a week I had a real nice even flat of tomatoes. My only real expense was the thermostat I had ordered from Grainger Supply for around $80. I thought I had really done it! I soon made another unit that held 14 trays, and it became my main unit. I also put a plexiglass top on the first one and put a light box on top for seeds that need some light to germinate. What I discovered was that a dishwasher has very little insulation value. When it was colder at night in the greenhouse, the germinator would run a lot and make a lot of steam. But when the sun came out and the greenhouse reached 80 degrees, it would not kick in, so my flats would tend to dry out. Plus my light box made too much extra heat. We have an appliance store across the street from us, and they deal mostly in used stuff, so they always have junk outside for the recycle guys. One day as I was pondering what would work better for my germinator, I saw a whole row of junk refrigerators. I took some measurements and discovered that the large size fridge would make a dandy well-insulated box. (Some refrigerators are not deep enough from front to back to hold a 288 tray endways, which really cuts down the number of trays it can hold.)
I started over with a two-door fridge, the type with the freezer in the top and the fridge in the bottom. I just stripped everything down to the box and the doors. The freon was all leaked out so that was of no concern. By the time I was done I had a really nice empty box, top and bottom, but still in 2 compartments, so I took my jigsaw with a longer blade and cut out the floor in the top unit. I cut out the shelves that were on the inside of the doors since they take a lot of room on the inside of the unit. For some refrigerators it takes some prying and sawing to get them off because they are filled with foam, and I was trying to save the insulation in the door. There is a pretty good layer of foam behind all those shelves, so it worked out quite well. I was able to make a neat cut just through the plastic
liner and the first ridge of foam with a short blade just inside the seal and then pry the rest out with a prying tool. It is good to paint the bare foam white because it will discolor some if left unpainted. It seems to be waterproof. For shelves I went to our local Lowe s Store and bought some nice 16 inch deep closet shelves
and cut them to fit inside the unit. The shelves are 23 inches long plus the pegs on the ends, and I can put two seed trays to a shelf. Plus I can get six pieces out of a 12-foot section. The guys at Lowe s are usually very nice about cutting the shelves just as you want it, so with some planning you can avoid having to cut the shelves yourself. The main thing is to have the amount of shelves that you want for your operation. I wanted 40 trays, so I crowded the shelves together. Mine are on 2-3/8 inch centers. These shelves had an edge on the front hanging down about 1-1/4 inch to give it stability. I put it to the back so it's out of the way.