Certain gardening terms, like "moist, well-draining soil" and "bright, indirect light", can be somewhat ambiguous. You can add "as soon as the soil can be worked" to that list. What on earth does that mean? As soon as you can get your shovel in? As soon as you can turn it?
The answer is not really as mystifying as it seems, but it's not straight forward either. It mostly depends on the weather and how damp or cold the soil it.
But different plants will have a variety of soil requirements, so not only do you need to judge the soil itself, you also need to consider what you will be planting.
Three Ways to Test if The Soil is Ready to Be Worked
- The Shovel Test: The simplest test is whether the soil sticks to your tools. If you put your shovel in the ground and it comes up clumped with mud, you'll have to wait.
- The Crumble Test: A more accurate test is the crumble method. Form a handful of soil into a ball in your hand. If it crumbles apart with a slight touch of your finger, it's time to plant. If it holds together and requires pressure to break apart, it is still too wet. (And if it won't form a ball, you can plant, but you'll need to water.)
- The Sit on It Test Some gardeners take the simple approach. If you can sit on the soil and not feel cold or damp, your soil is ready to be worked. If it's comfortable enough for you, your seeds should be fine. This test is not terribly accurate and there are seeds and plants that are much hardier than you or I, but it's a decent general gauge.
This is a good rule of thumb for when you are preparing potting soil for indoor starts too. Water the potting soil to crumble consistency, before you will your pots.
Why Wait to Plant Until the Soil Can be Worked?
Most seed packets will give you some idea of when you can plant the seeds directly in the ground, but knowing when to plant seeds cannot be determined solely by looking at a calendar.
Weather can be unpredictable and your garden soil will not be ready to plant on a schedule.
Soil often needs a few weeks at the start of the season, to warm up and dry out a bit. This is all the more true after a particularly snowy winter. The snow may melt, but it takes time for the sun to warm the soil that was underneath it enough to thaw it out and drain away all the excess moisture. If you have a warm, sunny spring, that will help to speed things up. If you have a rainy spring, the ground will probably still thaw quickly, but the sol will be water logged.
Seeds planted in cold, wet soil will simply rot. There's no point in rushing to plant. Even if you treat your seeds so they can handle the dampness, seeds planted a few weeks later, in more ideal conditions, will quickly catch up.
Plants can handle a bit more moisture than seeds, but even they don't want to sit for weeks with their roots in wet soil. Rot root is hard to stop. If you are moving a plant from one area to a similar spot, the dampness won't really matter. But hold off on transplanting container plants until, well, until the ground can be worked.