Propagation House: Space Saving Tips
Okay, so we are all SUPER EAGER for spring to be here and we are seeding like maniacs. Give me one afternoon and you know what happens? I can fill every surface in the greenhouse and it wont know what hit it.
So instead of seeding yourself out of greenhouse and home, what techniques can you use to make sure that everything keeps moving along in the right direction without too much “space crunch!” in your greenhouse or under your grow lights.
The Germination “Short Stack”
The Germination Short Stack is a great way to keep on top of your seeding schedule, without taking up any space on your prop house tables. In this picture I am germinating Lettuce seeds in 128 cell trays. I seeded and watered them in really well, stacked them up and placed an empty tray on top. This lettuce, kept out of the sunlight will probably germinate in 3 days, You’ll want to check it and spread these out once you see the roots pushing out of the seeds and before the seeds start lifting up towards the sky. Since there is no light in between the trays you cant let them stave and stretch for sunlight in the stack and timing is critical. Once you get in a flow with this it works really well. Midsummer I might move my lettuce germination short stack into the enclosed shed where it will stay even cooler. At Fields Edge Farm, lettuce seeded on a Friday was put into the ‘warm room’ (set to 55* F) and moved out on Monday first thing. Since the short stack is stacked, the moisture stays just right without evaporating too much. This is best suited for propagating with plug trays and wouldn’t be ideal for soil blocks for example.
Start Small & Dense
Another space saver is to seed into a densely planted open flat (a tray with no cells), a row tray, or a small cell tray (pictured is a 409 cell tray). You can seed 400- 1000 seedlings in these flats and only take up 10’’x20’’ instead of seeding directly into a larger cell plug flat. Seedlings are likely to sit in these small cell trays on heat mats germinating, and growing just enough for 2-3 weeks. Once they have a little root and some leaves they can be potted up (pricked out, spotted, or up-potted) into a plug flat with larger cells. For tomatoes the typical plan is to seed into a row tray, then 3 weeks late pot up to a 50 cell tray (or soil block!), and 3 weeks later pot up to a 4’’ pot (or Soil block!) until its ready to go into the field or greenhouse.
( Tomatoes in 3’’ pots taking up too much space for their size )
Go Vertical
Depending on the angle of the sun, you might be able to put things on shelves and still have plenty of light. In this picture you can see that I relegated the decorative flower seedlings to the floor and the lettuce crop is on a shelve above it. The seedlings aren’t leaning to reach the sun so that is a good sign that they have all they need. Being on the floor can create challenged though- especially if rodents have moved into your greenhouse- beware of that.
Kick ‘em Out
Rotating the more established seedlings out of the greenhouse is a good option when the greenhouse is overflowing. Its important that they get eased into the harsh life of the outdoors before they get planted anyway and this will give you precious bench space for other items that need consistent germination to get going strong. Of course, another option is to choose to direct seed your crop instead of start it in the greenhouse. But for me, I find myself choosing to transplant more and more items because of the consistent, controlled, and early germination I can get in the greenhouse. This inclination towards transplanting means that salad mix, spinach, beets, and peas are taking up space in my greenhouse right now. The quality of the crops will be that much better as a result, and it probably means that I will need a bigger propagation space before too long. But until then, Ill keep using these techniques to maximize the small greenhouse I do have and I wish you luck your spring shuffle.