Gardening Tips: Making Mudpies

What to do this week

Back in the day, when I got ready to start my transplants, it meant rummaging through my collection of old flower pots, cell packs and cut-down milk cartons. Like all good gardeners I tried to recycle and my Scotch soul hated to buy new plastic containers. Then I discovered soil blocks. An elegant solution in all the ways. Nowadays I use nifty mechanical blockers because I make hundreds of them each year, but for a long time, I just used some old square flower pots with the bottom cut out.

The principle is simple: start with the soil mix. To make your own mix, take three parts peat moss; two parts garden soil; one part good, well-aged compost; one part vermiculite or perlite. I use those big 11L ice cream buckets as my measure and add about a cup of garden lime to counteract the acidity in the peat moss. If your garden soil is heavy in clay, cut back on that portion a bit. Make sure the compost is well-aged – unfinished compost secretes chemicals that actually inhibit germination. The dust from the vermiculite or perlite can irritate your lungs so be a bit careful not to breathe it in. If this seems like too much trouble for just a few blocks, or if you haven’t thoughtfully put aside some garden soil last fall, you can just buy some soil mix for seedlings from the garden center and add one part compost or worm castings to three parts mix.

The author's soil blockers. (Photo by Michelle Smith)

The author’s soil blockers. (Photo by Michelle Smith)

Add enough water to make the mix quite wet (think: mudpie consistency). If you’ve forgotten the joys of mudpie making, this is your chance to relive your childhood. I use a plastic tub and cover the work surface with a blue bag to contain the mess. Scoop up the mix with your hands and ram it into your block mold, squeezing it in until the excess moisture runs out. Then tip it out onto a waterproof tray. Just like a sand castle but with dirt. You can even make a tray by lining a shallow cardboard box with another blue bag. (Once you’ve done planting later in the spring you can rinse the bag and use it for your recycling.) The blocks should not quite be touching on the tray. If you make a mistake and the block crumbles or squishes, just throw it back in the tub and try again.

Sow the seed on top, cover with clear plastic just until you can see it sprout, then take the plastic off and let it grow as usual. Water the blocks from the bottom up. Capillary action will move the water to the top. If you accidentally dry out the blocks – try not to, but it does happen – carefully dribble a little water on the top to start the flow. The blocks will be a bit fragile at first but over time they will fill with root mass that will hold them together.

There are benefits to the plants from this fun, messy technique. First, a soil block holds more soil than the equivalent cell in a cell pack, which gives them more room to grow. No lip on a flower pot to capture moisture means better air circulation and less risk of damping-off disease. Most seeds require light for germination as well as warmth and moisture. Sowing the seed on the surface of the block means they get all three. Just make sure you take off the clear plastic as soon as you see signs of germination. The only seeds you want to actually plant inside the block are corn and squashes. They need to absorb a lot of moisture before they grow, and they will just dry out or get moldy on the surface. Gently poke these seeds into the fresh, moist block.

In a flower pot, the roots will tend to circle around the perimeter of the pot instead of growing evenly through the middle. With a soil block, the roots hit the air space and prune themselves, filling the whole block with a lovely, dense root system. This way there is no transplant shock. Just take a spatula (from the thrift store, not the kitchen) and lift the blocks into holes in the garden. Cover the block with dirt and the seedlings won’t even know they’ve been moved. They just know that they’ve got more room to grow. This is especially helpful for transplanting the squash family which is notoriously sensitive to handling at the roots, but it means that all plants are more forgiving of other planting-out stresses like wind and moisture loss. Certain perennial flowers that don’t transplant well can also be started this way and encouraged, thereby, to bloom the first year.

The block size I use varies according to the plant. Onions, lettuces and perennial flowers all go in 2” blocks while tomatoes, peppers and eggplants go in a 3” block. I use a hand-made 3” blocker, since the mechanical blocker size jumps from 2 to 4 inches and the bigger blocks are simply too unwieldy. I use the big ones occasionally for special seedlings that I want to keep protected in the greenhouse a little longer.

I also like to do multi-plant blocking by sowing six onion seeds in each 2” block. Leeks at four per block. This saves time transplanting in the spring. I place each little clump of onions about a foot apart in the row and they push each other out into a circle as they grow. As I mentioned last week, onions are heavy feeders and are started early so they spend a long time in their blocks. Every two weeks I add some fish fertilizer to their water while they are in their blocks to keep up the fertility. Corn can also be grown in a multi-plant block, three to four in each 3” block, then planted out in hills.

Next week, we’ll take a detour through the flower garden with tricks and tips for starting finicky seeds.


Market gardener, farmer, workshop leader, seed-saver, political candidate and mother, Michelle Smith has spent over 30 years coping with the challenges of our bioregion and in the process has built a store of practical and technical knowledge. The Inverness resident has served on the board of Seeds of Diversity Canada and represented Alternative Producers with the Federation of Agriculture but can do nothing about her hair. She is pictured with a head of Club Wheat, a seed that shares her approach to hairdressing.




Backyard food gardener Madeline Yakimchuk caught the food-security bug in the early ’90s through Cuba’s Urban Agriculture Department, taking her first permaculture course and planting her first garden. She can often be found discussing food security, nurturing a plant-based lifestyle or trying to give away vegetables. Professionally, she is GRYPHON media productions but sometimes uses la bruja in her volunteer work, most notably in managing the garden column, which begins life as a telephone interview.





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