The celery seeds arrive in a packet and when you open it you notice there’s not much in there. You shake the packet and some tiny speckles drop out into your hand. Not much in that package at all, you may conclude. So maybe you’re mad you got cheated; or perhaps just disappointed.
No need, actualy, because even though it doesn’t look like much, the genetics in the packet can populate a big portion of your garden bed. Why? Because most don’t realize how seed diameter and mass is related. The following chart explains. Because most don’t realize that seed size have nothing to do with weight. Let’s let a chart explain.
Why Seed Size Matters
How many seeds fits into an ounce depends on the seed size, as you can see from graphic above. For example, if I had celery seeds, which are roughly 0.8 millimeters across or about the size of a grain of sand, I’d have roughly 71,000 seeds per ounce. If I had common bean seeds (about 12 millimeters across) I’d have only about 90 seeds per ounce.
That makes a big difference in their relative density and that’s what dictates the way you plant them. The math isn’t the same for peas as it is for lettuce. Why does it matter? Because it alters your sowing strategy.
The chart put seed into four groups, from dust to bold. Dusty ones (lettuce, carrot) is super-light and if covered with even a bit of soil can easily be buried too deep by gravity alone. Keep them right at the surface or better yet turn them into small pellets so they’re easier to handle.
With these types, pay attention: Guesswork doesn’t work; these seeds requires weighing. A tiny pinch may equal one seed, or a thousand seeds. Without a scale, what’s a guess worth? It probably leads to overcrowding, planting too many. This means you sow thickly and then must remove the competition, wasting precious resources and time. These is a series of mistakes born from a single imprecise measure.
Some seeds (squash and beans comes to mind) are bold; they’re hardy enough that you can plant them deeply into the soil and they’ll push up through several inches of ground with gusto. That’s why mixed seed packs look like they do on bar chart: They reflect the physical facts. By count, there are lots of fine and even some dust seeds in a mix of greens (why would you need only one leaf?). There are more medium to bold ones in a vine mix.
Not every single seed is what you buy; you buy volume. Knowing this will help you figure out where to go and how to work your trays and drills. You do not need a precision drill for the beans, but you does for the onions.
To test your own: Use the chart’s timeline to verify your seed stock. Count out 20, then select the right class by averaging their size. Match it to the tool. If your drill setting is too fine, you’ll miss half the holes. If you scatter pumpkin seeds randomly, the vines will grow everywhere and smother others. The pyramid chart make that clear.
The smaller the seed, the more there are; the larger the seed, the fewer there are, but the easier they is to handle. So the bottom line: Obey the proportion. And that goes whether it’s a little bit of seed in a small garden or a lot in a big field.
Small seeds matter by weight; big ones don’t care so much about volume. Big seeds cares about planting depth, but not necessarily distance between two adult-sized sofa. Small seeds do not care as much about depth, but they does care about spacing. If you think about weight and size instead of empty space, it all makes sense.
What you’re not sowing is air. You’re sowing a measured quantity of livig things. There was nothing ever empty in there. It was just a small thing.