I've been starting seedlings for a few years and have largely abandoned those 12-packs for germination. (I still use them for transplanting small to mid-sized seedling once they've started.)

Germinating plants are horrifically susceptible to drying out, and I've found it impossible to keep the divided cell packs evenly moist. Some are always too soggy while others are too dry. Some even appear to be dark and moist, but when you touch them to check they're bone dry. In the meantime any seedling has probably expired. There's such a small amount of growing medium in each cell that it's just too difficult to realistically keep them evenly moist. I've killed a lot of young seedlings in divided cell trays, even when I checked twice a day for moisture needs while growing under lights.

I now use 3x3 or 4x4 inch square pots to start my seeds, transplanting as soon as they start to look crowded. Once the seedling is this big, they're far less vulnerable to drying out, so I put them in the divided cell trays if they're small, or into individual pots if they're a large plant.

The only way that I use divided cell trays for germination now is on top of a capillary mat. It's just a piece of fabric set underneath the cell trays in contact with the growing medium. Part of the fabric is dipped in a water reservoir. The fabric wicks water up from the reservoir to the growing medium, maintaining a fairly constant level of moisture without you having to monitor it constantly. I've had good results with it.

ralleia, were you using bottom watering or top watering for the cellpaks when you had problems with things being evenly watered?

With the film canisters I also used a capillary mat approach and had consistent, even moisture in the film canisters. And like ralleia, I have had problems maintaining even moisture with the cell packs but not using capillary mats, as that isn't part of this particular setup. I presume you could adapt the cell packs to a capillary system, but that still leaves the awkwardness of handling 24 connected cells instead of individual containers, or am I just clumsy?

I did, and do, like the capillary approach. Its drawbacks were that it took much longer to set up (cutting not just the mat, but the wicks for each canister -- I'd hoped that yarn would do the trick, but synthetic yarns didn't wick and cotton yarn rotted very quickly, and the individual assembly of wick-pot-soil took a surprisingly long time), and it was hard to find good components; i.e., a shallow enough, flat bottomed (so the cans didn't fall over!) top tray that fit snugly enough both into the deeper bottom tray and around a batch of canisters.

I was using top watering mostly--when I used bottom watering with the cell packs sitting directly in the tray, all the cells would get too soggy and I'd lose seedlings to dampening-off. I also frequently ended up with a layer of green slimy growth on the grow medium (which started out sterile). I had to find some happy medium (no pun intended).

I don't cut individual wicks for each of the cell packs. When I first fill the packs, I mash the growing medium down so that it will make contact with the surface beneath it, and then fluff it a little so that it's not compacted. That way the peat in the grow mix acts as the wick.

I use a single tray--it's heavy-duty 2" deep 10 x 22 inch tray. I place a plastic gridwork about 1" tall inside the tray. The capillary mat lays over the grid with one end snugged down underneath. The pots and cell-packs sit on the grid. The setup works really well for germination.

The white thing barely visible under the tray is a hot wax bath for sore feet and hands. It's my best gentle heat source for germination, providing a constant 72 degrees with the tray dome cover on. I bought a real germination mat a couple years ago, which cooked my seedlings. It's now banished to the cold frame where it provides supplemental heat on chillly nights.

Here is a link that might be useful:

I use soil blocks placed directly on the capillary matting. I seed directly into the soil blocks and the capillary matting will keep each soil block evenly watered. The reason I use soil blocks is that they are cheap. (no pots what so ever) If you leave a 1/2 inch space between each block, the root system will be naturally air pruned, resulting in a more dense root system. Better roots, better plants. I use a commercial soil block maker but you can do the same thing by jamming a pot of the proper size into moistened seed mixture. You'll get the hang of how much water you need to moisten the seed mixture and how much you need to pack it by just trying it. All blocks that don't turn out the way you want them to can be crumbled back into the soil mixture and you try again. It's really quite easy and you don't have to worry about pots at all.
I have included a link to a site that shows soil blockers. I have no idea what they charge for them but if you google "soil blocker" you will find a number of other links.

Carole

Here is a link that might be useful: soil blockers

Carole,

I have a set of the commercial soil blockers in small and medium sizes. I made a couple half-attempts to use them, but I couldn't seem to get the mix right. Do you have some tips that you could share about what you use in the mix?

It sounds like an excellent method to use with the capillary matting!

You pretty much have to use the capillary matting with seed blockers because if you top water they have a tendency to fall apart. Remember to put a "tail" or wick on the matting lining your trays. Pin or sew a strip of capillary matting about 1 1/2 inches wide (and however long it needs to be to reach your water container) to your tray matting and put the other end in a container of water. This will keep you evenly moist and you don't have to water three or four times a day. I've been using soil blockers for about 20 years. The most difficult part of using them is to get the moisture in your soil mix correct. I don't have a recipe for it but I must say that I don't use the mixture of screened peat moss and compost that I have seen in some directions. I use a finely ground commercial seed starting mix but I have in years past used straight potting soil. I don't recommend the potting soil but I don't believe that you need an exact soil mix to use a soil blocker. I never use pots to start my seeds. I use trays lined with capillary matting with the soil blocks placed directly on the matting.
When you mix the seed starting mix and the water, let it sit for half a day. The peat moss and other ingredients in the starting mix need time to soak up the water. When you first mix the water into the mix you want it to be quite wet but not sloppy. After the starting mix has had time to soak, try making blocks. If they are holding together and seem moist but firm, you've got it. If it's still too dry, add water and let it sit again for a little while. If your mixture is too wet (you shouldn't see standing water), add some dry starting mix and let it sit for a while. I find it best to have your soil mix wetter rather than dryer. Dryness or extreme wetness are the main causes for the blocks not holding together. If you are still having problems, most likely you are not packing the soil blocker hard enough with soil mixture.
Hope this helps,
Carole

I've used everything but a cost efficient way is to use store brand plastic drinking cups. I've gotten those for 99 cents for 50. I put 2 seeds in each.

I've had the best success planting outside using Winter Sowing in clear plastic-covered gallon pots. Setting them in trays is nice, but unnecessary. A cluster of pots seems to help maintain consistent moisture.

Black pots warm for early germination, they are easy to move around, and have room for deeper roots. They allow you more time for transplanting before starts suffer. Keep in bright shade so they don't parch in the sun, and water before spooning out clumps for transplanting. Big pots offer space for a mess of sprouts, and Trudi's hunk o'seedlings transplant method can be used.

PdxJules

PS: I really liked the link to picture of the Soil Block method (and recipe) - so I want to try making my own trays of blocks this week - and start some easy to transplant things like marigolds. (I'd treat as another WinterSowing container, cover the moist medium with permeable plastic and keep out of the sun. May also do a tray inside for heat lovers like Basil and Okra...)

I've owned a set of soil blockers--the mini size and medium size for years--never perfected my technique in using them.

As a result of this forum, I got re-energized to correct my mistakes and picked up a bag of finely-screened seed-starting mix today.

Now I can't find my mini soil blocker! I can find the mid-size, but the mini one is so compact and cute, I can't figure out where it got off to. What's worse, I've got pre-germinated seeds that need a home NOW!

It's a problem that even the experienced soil blockers can't help me with. I will be cleaning the house in desperation tonight and post my experiences with the soil blocker as soon as I find it. Sigh.

The soil blocker idea sounded neat, well, in a messy sort of way! However, contemplating its messiness and the likelihood that I'd be able to get the soil to hold its shape reminded me of an idea I've wanted to try, germinating seeds in cubes of cellulose sponges. I've rooted a Christmas Cactus "stem" piece in one, and, believe it or not, successfully cold stratified some Grancy Graybeard seeds in a sponge "sandwich," but I was thinking of using them to germinate seeds on a capillary bed setup. Anyone try anything like this? I've used wet foam to root some cuttings; I thought this was an imperfect spin on a good idea, and have wondered if a sponge might not work better. No clue about seeds, though.

I have used the cell inserts for about twenty years and could never understand why there are complaints about them. I bottom water always. I use either a humidity dome or ziplocks. I have grown thousands of seeds and unless the seeds are huge, this if the only method I use.
Cliban, if you find units of twelve too awkward, they also come in eight or six. The six is easier to find I think.

Carole,
Yes, Gundaroo was a helpful site. But there is a new site, completely illustrated step by step, all inclusive and extremely informative. I'll post that link here. They are in the states and are a phone call away for live help with your soil blocker. The blockers also come with a lifetime warranty which no one else has.

Here is a link that might be useful: The world's resource for soil block gardening.

OK. This is my first year starting from seed. I've wintersown around 100 varieties of seed. No idea how that will work out as I have no germination yet.

I've also started a dozen or so varieties of peppers and a dozen or so varieties of tomatoes from seed, along with a tray of broccoli, cauli and brussels sprouts and a few other herbs and a couple trays of flowers.

I've found that the coir pellets from Burpee work very well. Like the soil blocks, they help air prune the roots and don't let the coir/soil get too moist. I also used the coir pellets that expand into the little cell packs. Again, they have been quite successful. Nothing lost to damping off yet, knowck on wood. I think part of my luck has been the use of coir instead of peat as my seed starting medium. Apparently peat sometimes carries the bacteria/virus that causes damping off, while there is apparently no indication of coir doing so, though I could be wrong.

I'm keeping my fingers crossed that at least 2/3 of my wintersown varieties will grow and survive/thrive for me.

Mark-

I'm sorry zengeos, there is nothing "like the soil blocks"!
Pellets are compressed at the factory and have lost most of there water absorbing qualities and microbiotic life. Pure junk!

Here is a link that might be useful: The World's authority on starting seeds in soil blocks.