When do I transplant?
Most of your blocks will be of the 2" block. Studies have shown that plants in blocks have the best growth transplanted at 2 weeks old. Different species, varieties, climates, conditions and markets will dictate the transplant time.
The most important factor to consider is uninterrupted growth, which means, the plant has a measurable amount of daily growth in relation to the size of the block which can not be disrupted or delayed. For example: Most seeds planted in the Micro 20 will have 6-10 days after they have fully germinated and shed the seed coat before needing to be transplanted. Most seeds planted in the Mini 5 will have 10-21 days until transplant. Most seeds planted in the Mini 4 will have 14-28 days until transplant. Transplants held in the Multi 6 can last 4-6 weeks, and the Maxi 1 will hold transplants up to 2 months.
Germinating seeds in a greenhouse or row covers, like slitted row covers, or Agribon row covers can speed up the process. Transplanting out in the open may set your plants back if the weather is not warm and calm. Hardening off is highly recommend. A little exposure to the elements every day for a couple of hours will work miracles in the end!
Always transplant at dusk! This is a secret key to gardening. Your plants can adjust to the new home during the soothing hours of darkness. For all practical performances, always transplant before the block becomes root bound or the roots turn from bright white to brown.
How do I set out transplants?
Before "setting out" your blocks, make sure and water them very well. Moisture in the block is essential for rapid growth in your garden. It is even more important than the moisture in your garden. Only after the block is established in the soil, with it's roots, is the moisture in the garden soil will be more important as the roots go searching for water.
Set out plants on a cloudy day or bring shade, or wait until late afternoon. We transplant at dusk; hint, hint. The key is soil warmth. A couple of sunny days before transplanting would work out nicely for you. You actually can begin to "harden off" your plants up to a week in advance of planting them outside. Soil blocks need very little hardening off compared to other methods, due to the roots being completely protected and "air pruned". Place your trays outside for a 1/2 hour to 45 minutes on the first day, and double that time every day for a week. This could be a lot of work, if you don't have an E-Z Wagon or a Vermont Cart, or a dedicated "hardening off" bench, shelves or tables, but well worth the trouble. Now, mark out your soil with the correct transplanting space and distance. A landscape rake with removable hard plastic tubes called row markers, that come on and off the rake teeth, can make real quick work of this task. Johhny's Seeds sells them, it's an Eliot Coleman design.
Next, you'll need to make a hole in the soil. We have found no better tool than the indispensable triangle hoe. It jabs the soil at the perfect depth and pulls the soil back and leaves a square hole.
But, the best home-made tool for setting out transplants is the dagger-style model using a bricklayer's trowel with a 2x5-inch blade. It's easy to make one: Cut off 2 1/4 to 2 1/2 inches to shorten the blade, then bend the handle down to below horizontal at about the same angle that it was above. (See here.)
They can be used to lift the blocks out of the tray, too. If the blocks are stuck together by their roots, bring a knife along to slice them apart. The Hori-Hori weeder/cutter works wonders and comes with a belt sheath.
Now, place the block lightly in the hole and firm soil all around the block, leaving no air pockets. Make sure to cover the top of the block, too, level with the surrounding soil. Soil contact is vital. You should not see the block anywhere. Some crops like to be sunk in deeper with soil covering more stem, like brassicas or tomatoes. After finishing your transplanting, water the garden thoroughly, but this is not entirely necessary for a couple days.
Interestingly, in Holland, greenhouse production of lettuce is done with soil blocks right on top of the soil. No hole digging! We have tried this method, and it works great. Keep it to the greenhouse, though, the outdoors would be too harsh.
Make sure and keep the entire block watered well. This method works well with the 2" block for baby greens, or the 4" block for full sized heads. They can sit on bare soil, plastic mulch with holes cut for the roots to penetrate the soil, or on top of cardboard. We also have placed blocks in thick mats of straw and hay right on top of the ground.
Layer up straw and hay or mulch about 6-8" in the fall and top off in late winter or early spring. Then, when it's time to transplant, just pull aside some mulch and set your block right on top of the bare soil. Pull the mulch around the block and cover completely, once again, leaving no air pockets and no tops of the block exposed. Keep your eye on moisture level, as the straw and hay act like air wicks and tend to dry out the blocks quickly.
The extra volume of potting soil in the blocks have another advantage. It puts valuable "organic matter" back into your garden. If you were to plant lettuce at a spacing of 12 inches by 12 inches, the amount of organic matter in a 2" block would equal 5 tons of compost or manure per acre! And, peat and coco peat lasts 2-3 times longer than manure or compost. The soil builds up extra organic matter planting after planting, justifying the added expense of using potting soil for block making.
When transplanting the 4" block into the garden, you'll need to use a post hole digger to create large deep holes. New to our farm is the ergonomic post hole digger by Fiskars. Finally, a smart design that eliminates knuckle smashing and it does not disturb the hole when you pull it out. It is well worth the investment if you plan on transplanting a lot of "hot crops" (grown in the 4" block) into the greenhouse or field.
For larger 4" block transplanting operation, the 4" should have been placed on a greenhouse floor covered with greenhouse plastic. Large reusable rubber mats can be custom cut and they last forever. You can also buy smaller rubber mats with rubber lips around the edges for extra water holding abilities. But, using them will impede your next transplanting procedure.
You'll need to have a manure fork ready to slide under the blocks and lift them up by the dozen onto an E-Z wagon or Vermont Cart. The mats with the lips get in the way of this smooth process, so don't use them if you plan on having more than about 150 4" blocks at one time. The angle of the manure fork is perfect for block transplanting. Less strenuous lifting is achieved by using a smaller manure fork.
What are Multiplants?
Multiplants are the only exception to the "one seed per block" rule. Multiplants are the practice of planting many seeds in one block, known as the "multiplant block". Depending on the plant being grown, anywhere from 3-15 seeds are sown in one block with no intention of thinning. Multiplant growing saves time, greenhouse space, and is the most efficient way to grow certain crops.
The concept is to clump the crops together for ease of seeding, transplanting, weeding, and harvesting and marketing. You will do the same amount of work for one block, except you will be growing 3-15 plants. These specific crops can grow in bunches in the same density per square foot as they would grow in a row. The onion is the classic example, and the model crop for the multiplant grower. If you were to grow large bulb onions in a row, you would need to plant one every three inches in a row, growing one foot apart from the next row. That would give you a total of 4 plants per square foot. With multiplants, you would seed one block with four onion seeds and place them every foot in a row, one foot apart. They will gently push apart from each other, creating large, healthy, blemish-free, bulbs. They get their space around them, and it makes for easy weeding. However, they do need to be transplanted sooner due to the increased competition for the limited space inside the block, and they need more water and be buried deep in the soil.
Seeding multiplants is most accurately done by creasing your seed packet and tapping the right amount in a measuring spoon or a seed spoon, and then dump them in the block.
The crops that have done the best in multiplants are onions, scallions, shallots, leeks, beets, spinach, pole beans, peas, corn and parsley. Crops that are normally bunched for market can now be bunched in the field, like scallions and beets. Crops that are rarely transplanted like spinach, beans, corn and peas can now be efficiently transplanted for a super early crop. Being the first in the neighborhood with sweet corn and peas will do wonders for your gardening reputation or market share!
In addition to these favorites, Europeans have successfully grown broccoli, cabbage, turnip, cucumber, and melon, but we have not had that good luck ,or trying it would not fit our farm model.
Make sure to read your seed package for proper spacing and then equate the same amount of plants for the recommended number of seeds per block given here.
3 seeds / block: cabbage, cucumber, melon, peas
4 seeds / block: beet, broccoli, corn, leek, spinach, turnip
5 seeds / block: bulb onion, shallots, parsley
12-15 seeds / block: scallion onions
Note: Start all seeds in the 1 1/2" or 2" blocks. Cucumbers and melons started in the 3" blocks. 15 seeds in the 2",3" and 4" transplant block. The 3 and 4 inch block will NOT need to be potted on later.
What about fertilizing?
If you do not use the base fertilizer, you will have to fertilize your plants in about 8-10 days after germination. The best reason to mix in a base fertilizer is to save time. The base fertilizers suggested are all slow to medium release. This gives your block plenty of nutrients over the course of days or weeks to grow vigorously. If you opt for the simple mix or a commercial mix without any fertilizer, you will need to fertilize with an organic liquid based fertilizer. We use our compost tea, a highly effective, all organic fertilizer, with lots of microbial action. We also mix this with cold processed liquid kelp. You can also use enzymatically digested fish emulsions, compost tea, manure tea, Earth Juice, or any other "cold processed, lab tested high microbial, enzymatically digested" organic fertilizer. Read and follow directions carefully. More is not better.
Where and How do I place my blocks?
Soil blocks can be placed on a wooden board, plastic sheets, or existing plastic trays left over from your old system! Pieces of greenhouse plastic work great.
After your first row is ejected, you'll want to place the next row of blocks 1/8" away from the first. This keeps the air in between the blocks so the roots do not intertwine with each other.
Always have a small bucket of water next to your blocking station to dip your blocker in before each charging. This keeps the metal lubricated for easy ejecting, and keeps the acids from corroding the metal.
Our favorite method is to place greenhouse plastic over your thermostatically controlled heating pad. We love to use the big 2' by 5' thick orange rubber pad. (Email us to order them.) Cover completely, then frame the outside of the pad with 1"x 2"s or 2"x 2"s. The blocks will need to be moved one more time, though. (Use our Season Cycles soil block organization chart.)
You can make a specially designed potting block tray that can be stacked and moved around for transplanting. This tray can be made out of 1/2" plywood for the bottom and 3/4" stock ripped down to 2 1/4" for the sides. You only make three sides, as the one open end is used for easy unloading. The inside dimensions will be 22" x 8", so account for the 3/4" inch sides. The 22" holds 44 2" blocks, 75 1 1/2" blocks, and 21 3" blocks. A smaller tray can be made for the home gardener. It has an inside dimension of 18" x 8". It holds 36 2" blocks, 60 1 1/2" blocks, and 18 3" blocks. Nail with galvanized 1-2" finish nails or screws. All along the top 1/2" of the sides, drill small 1/8" holes every inch. This draws in air, and keeps the air moving along the tops of the germinating seedlings when the trays are stacked, which prevents damping off. See "Trays, Trays and more Trays" at our Blog.
Micro trays are made with 1x1" sides and are only half the width (4") of the others. You can keep two micro trays side by side for a modular effect.
How to seed and water potting blocks.
First, choose the right size pin for the seeds you will be starting. Use the seed pin for small to medium sizes, the dowel pin for large seeds, or cuttings, the cubic pin for extra large seeds or micro block transplants ("potting on"). After ejection, the block will contain a pre-drilled hole ready for seeds.
Since seeding in potting blocks have a 99% success rate, it is very important to seed each block with only one seed. Lay out some seeds in a dish or piece of paper. Use a sharpened wooden pencil, a matchstick or a toothpick, and dip in a small bowl of water. Then touch the seed with the stick and it will stick to it. Transfer the seed to the hole and touch the block. The seed will stick to the block because it is wetter. Wet the stick every few times. You can also use mini hand-held vacuum seeders (Tenax Pro-Seeder), seed spoons, seed sowers, or crease the seed packet and tap one in at a time.
You do not have to cover the seeds, but the brassica family crops do better with a layer of sifted (1/4") blocking mix over the seed. You can cover the entire tray or trays with black plastic. This works very well for the brassica family and lettuces. Some flowers need light, some dark. So read the seed packet carefully. Some seeds like a little sifted potting soil on top. Use a bonsai sifter, or some 1/8" hardware cloth.
Check every day until seeds sprout. They won't need any water for about 2-3 days. Then, they will need a very gentle watering. We use Fogg-it nozzle misters attached to Brass adapters sometimes on a regulator thumb valve. They deliver a perfect amount of water for every stage of growth. Use the 1/2 gallon per minute for seedlings. The main idea is to keep them moist. Water the blocks thoroughly. Leave no corner dry, pay attention to drying blocks as this could stunt them and make it very difficult to re-wet the block. (If they do dry out, soak block in a half inch of water for a few hours, known as "bottom watering".)
The older the seedling gets, the more water it consumes. Move up to the 2 gpm Fogg-it nozzle, when you notice rapid growth. Blocks are strong and can handle a good deal of water. "Be consistent and persistent, considerate and polite! Keep them moist morning, noon, and night, and you will be alright!"
At first, this seems to be a lot of work; seeding one seed at a time in each little block. But, this is almost the end of your work. Soil blocks eliminate the thinning process. Each seed is planted individually, each block is transplanted at the perfect distance. If a seed doesn't come up, no big deal, the loss of space is minimal and you can reuse the soil in the block. Just toss the block back into the tub to be joyfully compressed again.
If your seeds are old, or you need to test germination, germinate in another medium, and "prick out" the sprouts and place them in a block indented with the dowel pin and cover gently with a little sifted soil. So, remember, thinning is a lot of (back bending) work. But, bench top blocking and seeding saves time in the end.
Once you've successfully learned how to make really nice blocks, there's a tendency to make a whole bunch and seed them! This is a lot of fun! This is the time to make sure to log, map, or graph them out on paper or a computer program. Since there is not a pot to place a marker or a label, you'll have to rely on your map. Although you can slip a small, thin plastic marker in between the 3/4"micro block and the outside of the cubic pin hole on the 2", or between the 2" block and the 2" hole on the Maxi 1 4" cube. Since we are eliminating plastic "stuff" on our farm, we choose to graph our blocks on paper and slip them in a water-proof (oops, plastic!) jacket. Use a 4x4 Quadrille Ruled Graph notebook. They have four squares per inch. Depending on how you're laying out your blocks, use the 1" square to log info for the micro blocks, and 2" squares for the minis and maxis. Inside the square write down the name of the seed, variety, date of sowing, date of emergence, length of germination time. Keep a log down the side for pertinent information like temperature of flat and greenhouse, humidity, potting medium used, fertilizer used, and how the seedling performed. Or, you could try out our own Gardener's log, called "Season Cycles".
"Potting On" is like the nursery term "potting up", but in our case we are literally potting on top of a larger block. The smaller seedlings are set on top of a larger block for further growing.
Speedy germination of blocks using heating pads, are quickly transplanted to a larger block, making room for more seedlings. This is a tremendous advantage over pots. Time spent "potting on" is also reduced drastically. (Bare root seedlings take a lot of time to transplant.) The smaller block is simply placed right in the top!
You will need grow tweezers to move the 3/4" micros into the 2" block. You can make your own by fastening two wooden plant markers on a 1" dowel. Or, two cedar shims with a piece of sheet metal for the spring wrapped with duct tape works wonders. We have used wooden tortilla flippers, but now we use our famous stainless steel tongs.
You want to keep the seedlings growing, so as soon as they come up, they should be on top of the 2" block. Seedlings started in the 2" block can be kept longer, but transplanted before their leaves overlap. All the hot crops (melons, cucumbers, eggplants, tomatoes, peppers) are transplanted in the 4" cube. The Maxi 1 4" block is best placed on a sheet of plastic and can be moved with a metal blade kitchen spatula, or a large, strong cedar shake or shim. Wet the spatula or shim and slip it under the block. Hold steady with the other hand, these blocks are heavy!
Use a wide cedar shim to move your 4 inch block to a new location.
Use your other hand to stabilize it if it's too heavy.