Earlier this year I announced my plans to figure out hydroponic gardening. It seemed like the last frontier and a way to grow gorgeous lettuce in the winter. Alas, there is nothing growing hydroponically in my home. It just kept getting shoved to the bottom of the to-do list for too long and now it will be next winter’s best intention.
But hydroponics do figure in to my winter lettuce growing operation. Last summer and fall as I was gathering information about hydroponic gardening, I began to badger the people who work at the Brogue Hydroponics stand at the market. One young guy was particularly helpful and I explained to him my desire to get in on the hydroponic gig and asked if it would be possible to tour their farm. He looked around and quietly said, “No, they don’t really like anybody visiting the farm.” Hmmm. I don't know many secretive farmers. This peaked my interest.
I continued to interrogate the nice young man every week. He told me that sometimes they join the summer farm tour. That was way too long to wait. Finally, exasperated by my questions, he said, “You can just re-grow the stuff you buy, you know that right?” He explained that if I tore off the lettuce head from my newly purchased lettuce. I could replant the bottom of the head, the part that is still in soil when purchased. I asked if I needed to plant it in water or if I could just put it in dirt and he shrugged his shoulders. “Would probably work in either.” I went home happy with my new information.
The previous weekend, my husband had finally built me a cold frame (don’t be that impressed, I’ve been asking him to do this for nearly ten years.). He strategically placed it on our southeast facing slope just below the blueberries. I think this is strategic, not just from a sunshine angle, but also to discourage me from adding another row of blueberries (as I did last year).
|Baby lettuce about three weeks old. Yes, I realize|
someone needs to weed this.
|Don't be distracted by the handsome cat, just look|
at that lettuce!
|Wowee - wow, wow, wow!|
Cold frames are very simple to build. I asked my husband what was necessary and here’s the response I got. I need to warn you that he’s an engineer, so there may be more information here than you necessarily need and it may sound more complicated than it actually is. Fear not - you can do this. It's basically a classic sandbox with a lid.
2 ea 8ft 2x12 (pressure treated) for the base
3 ea 8ft 2x4 (pressure treated) for the top
1 ea 26inx8ft clear polycarbonate corrugated roof segment. Also the 24in plastic “closure strips” to nail down corrugated (sold in same aisle of store)
Scraps for internal corner bracing, etc.
2 ea 8ft 5/4x6in Cedar deck boards (to line the box at/below soil line)
3 inch deck screws, 2-1/2in stainless screws, special fasteners for the corrugated roof material (also sold in that aisle)
Location: On a hillside facing Southeast. The hill is important because this box has no slope to the roof. In order to put on flat ground it would need a roof that has a pitch to allow rain to slide off.
Base: The finished dimensions are 4 ft x 4 ft. The base is made from the two 2x12’s, each cut to 4ft and then screwed together with deck screws at the ends. I squared it up then secured with scraps (diagonals) to keep it square as it was moved around into place. An approximately 4 inch deep trench was dug to get below the grass root level; lay in the base and double check square (diagonal measurements equal). Use the cedar (cut to length) to line the box down to the bottom of the hole, and fasten in place with stainless screws (not required but I had some left over from a previous job). This keeps most of the pressure treated wood out of contact with the soil while taking advantage of the long life of PT and Cedar in contact with the ground. Using regular pine or fir would only last about 2 years in contact with the ground. I was tempted to put in the dirt and fill the sides, but one never knows what will need to be changed, so fill in after all other steps are complete.
Made a 4ftx4ft square with the 2x4’s and then put in some corner bracing as well as additional studs to allow nailing of the corrugated (trying to use as little as possible to keep it light). Put on hinges and installed on the base to make sure everything is ok, square and matching up nice. Then nailed on the closure strips and 4ft long pieces of the polycarbonate. Note that the poly roof is a little larger than the box, but only 1/2in or so on a side. It creates a little bit of an overhang as a drip-lip. You don’t want too much or it will get caught on your pants or the lawn mower over time. Now that the box is all finished, fill it in.
I screened the soil before putting it back in the box so it is nice top soil with no rocks, weeds, grubs, etc. I used all the rocks to fill in the outside edge as this may also be considered good drainage and we have so many rocks we need places to put them. The sod goes in the woods since I don’t want to encourage any grass growing around the outside edges. Over time, the grass will grow to the outside edge then need to be weed-wacked. Now would be a great time to mulch around the outside of the box.
I also put a long 2x2 board on a screw to allow the top to stay propped open (like on a grand piano). As you lift the top, the long board extends and sits on the ground so the top stays open on warm days or to weed/plant/harvest. Also I put a few scraps of wood nearby to prop open the top just enough to let air in, but keep the chickens out. (Otherwise the inside of the box would get too hot)
Every time I go to the market, I look for the young guy who told me about re-planting my hydroponic lettuce, but I haven’t seen him at the stand since the day he passed along that information. I don’t want to promote conspiracy theories or anything, but it’s suspicious that he’s been missing ever since revealing one of their secrets. Who knew hydroponics was such a furtive agricultural practice?
If you decide to build a cold frame it can increase your growing season on both ends. Herbs like parsley and rosemary will most likely keep growing year round in a cold frame. Build it soon and you’ll be able to plant lettuce this month and harvest in late March! Oh, the possibilities! I’m hoping to convince my engineer to design me some taller boxes for next fall to ensure peppers and peas through thanksgiving. If he’s lucky, I’ll forget all about my hydroponic dreams!