From the humble beginnings of Eliot Coleman's New Organic Grower comes the World's Resource for Garden Soil Block Makers as seen on Johnny's Seeds.
Monday, November 30, 2015
The Most Frequently Asked Questions About Soil Block Makers
Q: All my various seedlings seem to want to push up out of the soil, exposing some of the roots. Is that a problem?
A: If a seedling is growing vigorously and rapidly, then there is no problem, they'lltuck their roots back down in the soil eventually. To prevent the delicate roots fromdrying out, though, patch the roots very carefully with wet potting soil. Pat it on the rootssoftly and stabilized the stem. That should help out fine. Try not to chargeyour blocks so much next time so that your particular soil blend is softer for the seedsto penetrate. Now next time you sow seeds, cover with potting soil, and place a black plastic bag over the top and weight down with some cardboard. You can use whatever is at hand, but the point is to weight down the seed firmly enough so that when it "pops" open the root gets forced to probe the soil block and stick there and grow down. This is the "weight-down" method, and can be used with whatever style or technique is readily available.
Q: I'd prefer not to have to mix-up a new batch of soil each time I plant. Is it feasible to make a month's worth of potting blocks at one time? If so, how would you "store" them before using?
A: Yes, you can make a bunch up and store them. Keep them in large flats or multiple flats and slide them inside a large garbage bag and seal up the moisture. Keep in a cool location. If they dry out, they're a lot more prone to drying out again, faster; the peat has "memory" so to say, as towhat it will do.
Q: I would like to know if you could explain the process of using the coconut coir fiber to make soil blocks? Can I use it with the micro(20) soil block maker also? Can it be used alone without any additives, just water?
A: Coco peat should never be the only ingredient, the blocks will not hold together. Coco peat must at least be mixed in with peat moss up to one half the "peat" ratio, or at least should be mixed 1/2 compost, 1/2 coco peat. The compost adds the stickiness which can hold the block together. The sphagnum peat moss adds the fibers that also hold together a block. Coco by itself really has no way of adhering to itself, even with water, so add those other ingredients. The Micro soil blocker will work fine with coco peat if it is sifted to 1/4", and, of course, blended with sifted compost and peat moss, too.
Q: Do you cover the hole with additional potting soil?
A: I like to cover seeds in the cabbage family with a pinch or two of potting soil. I like to cover most other seeds with a sheet of black plastic, like a garbage bag, to seal in moisture and heat, check daily, for sprouting seeds and remove promptly. You can do a combination of both aforementioned techniques.
Q: When working with potting blocks for the first time this year, I didn't have the fertilizer mix items when I made the soil blocks. I plan on adding fertilizer now that the first set of true leaves have appeared but what type or levels do you recommend for vegetables?
A: In our experience working with soil block transplants without the dry fertilizers blended in the soil block making mix, the best thing to use is: once every three days a weak solution of fish emulsion and kelp combo keeps them strong.
Q: I recently purchased a 4" (maxi) block maker from you and while I've got watering figured out for 2" blocks (I use a 3 gallon pump sprayer) I'm guessing that's going to take forever for a tray of 4" blocks.What's your favorite way?
A: A big watering can with a rose attachment works well. I also use a 4 gpm Fogg-it Nozzle. Bottom watering trays are effective as well. Fill them up to the top and the blocks will soak up the water readily.
Q: I am seeing a lot of white fluffy mould growing on my blocks and potting mix. Is this an issue?
A: This is a type of fungus, but not damping off, and it is good. It is natural and a symbiotic relationship with your plant roots. It is an overall sign of good organic matter in the soil blocks. See below for further explanation.
Q: Can vermiculite be used in place of perlite?
A: It can, but it is NOT advisable as vermiculite will crush and be rendered useless for soil block making, and it is very irritable to the respiratory system. Please avoid.
Q: Once blocks are made and on a heating mat, is it possible to keep the blockstoo wet? I'm not afraid of the blocks falling apart, I'm certain the peat will keep that from happening. What I do fear, or want to avoid, is the trial and error of having to repeatedly start seeds over because I drowned them with too much water?
A: You're always safer overwatering soil blocks IF you have fans on in your seed starting space, because soil blocks that dry out could stunt your plants.Don't DROWN them, but keep them CONSISTENTLY moist, but only after they havegerminated and are off to a good vigorous start.Don't worry about them falling apart, you'll see, begin practicing at once todevelop your skills. Fear not, push the soil into the chamber to the max, experiment withdifferent moisture levels in the potting soil with no attachments to the results.Just get a good feel for the perfect soil block, then seed.
Q: I'm curious to know if you've ever had a problem with seeds pushing themselves out of the 3/4" blocks?
A: Get a black garbage bag and a piece of flat cardboard. Then make a flat of micros and seed them. Cover the flat with the black garbage bag and loosely place the cardboard on top just for weight and check ever day to see when the sprouted and remove promptly when most seedlings have emerged. This light weight sealing technique will firmly seat the tap roots in the block. Keep groups of families separated like the brassica/cole crops separated from carrots, etc., so they can germinate in unison.
Q: What is this dip, air prune, and bottom watering tray stuff mean?
A: The bottom watering trays are the water tub and the soil propagation trays have a fine mesh holes on the bottom, and this is for air pruning. To use in combination with the Bottom Watering Tray, fill the bottom watering tray with half water and dip your soil blocks, which were placed in the soil prop trays, in the bottom watering tray. Let it absorb the water and remove, letting the soil blocks air prune again. In the spring do this once a day in rapid growing situations. Over a weekend? Fill up the bottom watering tray, while the mesh prop tray is in it, about 1/2 full, and it should stay wet for the weekend.
Q: In multiplant blocks, do you put all the seeds in the one dibble hole? The standard dibble?
A: Yes. Smaller seeds in the regular seed pin for multiplants. Use 1” dowel seeds for larger seeds in multiplants like beets, chard, peas, beans, corn, etc.
Q: What is "greensand?"
A: Also known as New Jersey Greensand: It is a naturally occurring marine sedimentary deposit. It is the mineral Glauconite that is used from these sea-born deposits of 80 million years old from iron-potash-silicates. It is a natural source of slow-release potassium (3%) used for long-term soil building of potassium deficiencies, opening up clay soils, and providing improving moisture holding capacities in sandy loams.
Q: I am a bit new to seed starting, always having used purchased transplants before. I am wondering why, as a home gardener, I would start with small blocks and transplant up to the larger ones rather than just using the larger ones to start the seedlings and the transplant those directly into the garden. I am not a commercial grower, just trying to be sustainable and grow food for several families. Am I thinking incorrectly here? I just don’t really see the advantage of using the small blocks and moving up. Maybe you can help me understand better.
A: Some gardeners know that transplanting stimulates plant growth. And, starting with the micro 20 blocks, one can save space and start the smallest and flattest seeds that take a long time to germinate, like tomatoes, peppers, eggplants, parsley, tiny flower seeds and herbs. The small cube helps retain heat for those heat lovers, as well. So, after almost 2 weeks of germination, some with irregular germination rates, one can then select the finest plants of the bunch and then transplant them into the 2" blocks for premium plants, no runts. So: Stimulates Growth, Saves Space, Heat Retention, Select for vigor, "Pot on" for best growth with those stated crops. It’s even been studied andprovenin Europe to produce bigger, better plants, and harvests are weeks ahead.
Q: What is lime?
A: Anytime we refer to lime in horticulture we mean “horticulture grade limestone”, which is at least 95% Calcium Carbonate, and/or “Dolomite limestone”, which is pure calcium carbonate and magnesium. Oyster shell is acceptable in soil block making, too. The goal is to stabilize Ph levels in the peat moss block mix.
Q: My soil blocks have a white fluffy mold on them, is this damping off?
A: The "white mold" is actually a fungus, but not the damping off type, and is an indication that blocks are indeed very wet which could lead to damping off, but is OK for now, it won’t hurt your plants. Damping off is an indication of overwatering and mostly: NO AIR MOVEMENT. So, you should be adding a fan in the germ room. The Humidity Dome works to keep heat and moisture inside for a germinating seedling, but should be cracked during the day to allow the fan and air to keep soil blocks aerated. Sterilization is not needed in soil blocks made with well decomposed compost and a reputable peat moss. Fungus is handled easily by lots and lots of air and oxygen in the room blowing on the seedlings and the blocks. Damping off fungus is only thriving due to low levels of oxygen. You need a fan!
Q: I don’t have any good compost for soil block making, and I don’t have good garden soil. What do I do?
A: Replace all the compost and soil parts in any soil block recipe with worm castings or vermicompost. You can find worm castings by searching in your local area for suppliers and back yard worm growers advertising locally in newspapers, craigslist, or farm and garden store bulletin boards.
Q: Why do you recommend using fans for starting seeds in soil blocks?
A: The use of fans are four-fold:
1.) Keeps the very surface of the soil block dry so that fungus gnats or other pests can't set up shop.
2.) Strengthens the seedling stalk by moving it back and forth creating tension fibers in the plant.
3.) Allows light to penetrate all parts of the seedling by moving the leaves all around distributing light to the canopy.
4.) Delivers fresh supplies of nitrogen found freely in the atmosphere to the stoma cells which will utilize as much air born nitrogen as possible. (That's also why foliar feeding works so well.)
Q: What is the difference between hard and soft rock phosphate?
A: Regular rock phosphate is mined from rocks from the earth, whereas soft rock phosphate is fossilized ancient marine sediments from the floor of the ocean or deposits left over from ancient seas. So, you can not get soft rock from regular rock. Regular rock will do the same thing, just very, very slowly. So, hard rock will work, but use it in your garden, and get it in NOW so that it can be used a little bit this year. It will be a good long term amendment for your garden soil. Go ahead and skip the phosphate in the soil block mix, or try bone meal, which releases phosphorus a little faster than hard rock. But, when it comes to seedling health, the “colloidal” phosphate is released to the roots immediately by the microbial action in the soil, giving the plant a head start on phosphorous.
Q: Do you recommend capillary mats?
A: No. At transplant time, you’ll end up ripping off all the roots. Use a tray that holds water and fill the tray up 2/3’s the way and let the soil blocks absorb the water over a span of a few days.