Spring fever can make us do funny things. Planting too early is tempting, but risky. Now, especially with the soil too wet to work for the next few days (as of 5/18/17), we're edging into late spring. Don't despair! Plant your favorite veggies, but amend soil with care.
But springtime is forgiving in the vegetable world. Our spring plantings yield at about the same time without too much impact of when we planted them. This effect has to do with air and soil temperature along with photoperiodism (the response of plants to day-length), and it means that lettuce seeded one month ago may be ready to eat only a few days earlier than lettuce seeded today. Procrastination doesn't hurt so bad in spring time!
The opposite is true in fall: lettuce sowed a few days earlier can be ready to eat weeks earlier! Anyone who has had the discipline to sow the same amount of lettuce once a week every week from March through September will have noticed a tremendous abundance of lettuce right when all the spring sown lettuce comes ready, then a steady supply of summer lettuce, and a disappointing tapering-off of production as it cools off.
This info is from Pam Dawling, author of Sustainable Market Farming. She's got tremendous experience in the market garden, but this particular insight is more for interest than practical for the home gardener. I'm happy when I have more veggies than I can eat, but sharing the harvest is sometimes better than eating it all myself.
Amend with care
Springtime is not so forgiving for harsher amendments. If your soil pH tells you to lime your soil, that ship has sailed. Lime at this time will wreck the delicate root systems of new plants. If you felt inclined to apply some heroic dosage of synthetic fertilizer (you're probably not reading this blog) but that too can damage young plants. Compost comes through in a pinch for procrastinators.
Compost is safe for plants in any amount, and not only does it provide fertility, it has a pH balancing effect on low pH soils as well. So skip the hard stuff and use compost. A layer 1/2"-1" thick on the soil surface will meet the needs of even the heaviest feeding garden plants.
One exception is compost with high salt (or EC, Electrical Conductivity, as it is reported on lab results). High salt compost is produced when lots of animal manure is included in the compost recipe. Our compost has a healthy serving of exotic manure from the zoo, but it's well balance with wood and yard waste to make a consistently low EC product.