So many vegetables and herbs, including arugula, broccoli rabe, pak choy, bok choy, mustard greens, basil, and lettuces, have the teeniest, tiniest seeds. I’m always surprised that they germinate. It just seems impossible that something so small could grow into a plant. I find sowing these seeds kind of nerve wracking because burying them too deeply is easy to do and results in spotty germination. So, over the past couple of summers I’ve developed a system that makes direct sowing tiny seeds easier. Here’s what I do:
1. Thoroughly weed the soil. Weeds compete for nutrients and can quickly crowd out small seedlings. If you’ve really had a big weed problem in the past try this before sowing: weed, rake the soil smooth, water the soil, wait two weeks, pull any new weeds that have come up—it’s a simple strategy, but it works wonders for reducing weeds.
2. After weeding, use a four-pronged cultivator or a rake to gently work the soil. Remove any rocks, clumps of soil, roots, or other debris and smooth out the soil until it is flat, smooth, and crumbly.
3. Water the soil. Seeds germinate best when they have good soil-to-seed contact and I’ve found that the seeds stick to the soil and stay in place better when it is damp.
4. Sow the seed. In order to evenly distribute small seed, it is often recommended to mix the seed with a bit of sand or potting mix. I’ve experimented with this technique and always come up with mixed results. So I have gone back to just trying to space the seeds as evenly as possible and then thinning out the plants after the seed germinates (the thinnings taste good, so don’t toss them!).
5. Water the seed in with a gentle stream of water from a watering can. This helps settle the seed into the soil. Don’t use a hose! The force of water from the hose can pick up the seed and you’ll end up with a big blob of seedlings in one end of the bed.
6. Finally, sift a light layer of potting soil over the seeds. Just barely cover them up. I use potting soil instead of garden soil because it is lightweight, weed free, and easy to evenly distribute over the seeds. I usually scoop up a handful of soil and then rub it between my hands so it falls in a fine layer over the seeds. Gently pat the top of the potting soil. Finish up by watering the seeds in again with the watering can.