There are some important things to understand about planting vegetable seeds outdoors.
The first is soil-temperature.
If soil temperatures are too cold, your seed is going to rot. That’s one of the major causes of poor germination – you’re trying to beat the season. No matter how enthusiastic *you* are, if that soil is cold, your seed is going to either sit and wait for the warmth or rot/die.
Rule of thumb: You’re better off waiting a week with most seeds than you are trying to rush the season. This is particularly true of the warm weather crops such as melons, cucumbers, squash and beans.
The second is planting depth
The main determining factor for good seed germination (beside warm soil) is ensuring the seed is in contact with moisture. We normally bury our seeds to accomplish this.
I say “normally” because when I controlled soil moisture in the greenhouses, I rarely “buried’ seed – I might have “just covered it” but rarely at the depth recommended by many garden catalogs.
Your job is to ensure a supply of moisture around the seed and to cover it with the minimum amount of soil to accomplish this. Seeds don’t need dark to germinate, they need constant soil moisture
With the exception of big seeds such as beans and corn that want to have their roots in the soil and have large initial roots, I barely cover all seed. I do plant the larger seeds down to recommended depths or they’ll curl out of the ground.
I cover most seed so I just lose sight of it. And then I pat it down so the seeds are in contact with the soil.
I much prefer to spend a few extra minutes in the day watering and making sure that there’s moisture around the seeds. I keep the ground in the seedling area damp. This ensures the seeds get good soil moisture and are able to germinate in the heat of the top layers of soil (rather than the colder layers below).
The problem with this of course is that you have to water properly. And firm the soil with a pat of your hand to make sure the seed is in constant contact with soil particles. If you’re not prepared to water once a day then you need to look at a slightly deeper planting (at recommended rates in the vegetable section)
Is that if I delay a week or so with the warm-weather crops, they’ll catch up to the earlier planted ones because they’re getting all the heat they need with less stress.
Cold weather crops can be put in when indicated; but I do watch the watering on them to make sure I’m using a lukewarm water (if possible) on the seedling areas.
How to Sow Seeds Outdoors
After the ground has been worked, I firm the soil by pushing it down with my hand or patting it down (firmly) with the back of a shovel. I want a smooth seedbed. I don’t want big cracks in the soil where the seeds can disappear and find themselves too deep to germinate.
With small seeds, they are laid down in as straight a row as I can make (if you’re more compulsive than I am, you can use string) and then barely covered over with soil. I pick up some loose soil and scatter it over the seeds with my hand. I do make sure all the seeds are covered or the birds are going to get more than I will.
With larger seeds, such as corn and beans, I carve a small trench in the firmed soil with my trowel or hoe and put the seeds in the trench. They are then covered.
Again, the seeds are kept damp.