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Every seed has one or more biological devices intended to prevent or delay germination until optimal conditions present themselves. In many of our most common garden vegetables, merely drying the seeds is sufficient to overcome their primary inhibition, allowing them to germinate easily in relatively warm moist soil. Some species that require consistently cool and moist conditions to establish themselves will be driven into dormancy by high heat, and these include some common salad plants like Lettuce and Spinach as well as many Umbelliferae like Parsley and Parsnips and even some Carrots. Slow-growing hardy herbaceous and woody perennials in particular will wait very patiently in frozen or parched soils until some specific duration or combination of cool and damp is detected and said mechanisms are affected, which signal to the plant that it is safe to germinate. In spring their collective seed minds decide:

When gardeners have difficulties germinating common salad plants it very often has to do with excessive heat. Some gardeners seem to wait until May to sow everything outside all at once, which is convenient but inconsistently successful. It is likewise tempting to start everything inside under lights, especially where winters are long and without the luxury of a greenhouse, but the temperatures that expedite the germination of Tomatoes and Peppers will prevent the germination of some other food plants, and Lettuce in particular.

Some unusual salad plants to sow into thawing soils: Spoonwort, the historic “scurvy grass”, is a fun alternative to watercress, Mâche, which really prefers to grow through mild winters but can be forced in spring with some success in the Northeast, and Sea Fennel, a rare and tasty halophyte that germinates best when subjected to several freeze and thaw cycles in well-drained garden soils.

The incredible diversity of species that grow best when exposed to fluctuating temperatures in spring is a revelation. Professional nursery growers rely on expensive and intensive seed treatments and growth stimulants for quickly germinating and propagating plants, but gardeners have the luxury of time and terroir, and years of experience have proven that patience and the annual machinations of nature are superior to any artificial or imposed stratagem. The wisdom to utilize the seasons to maximize what can be grown from seed in a given space is more valuable than anything that can be bought and sold.

Several other biennial root crops require some cold to germinate successfully, like the aforementioned Parsnips, but also Black Salsify, the silly Skirret, and the rare and aromatic Turnip-rooted Chervil. We tend to start Skirret indoors (the roots will not be straight no matter what you do), but the others should be sown directly into the garden. The Turnip-rooted Chervil is best overwintered outdoors in most regions but we have managed to get it to germinate when sown into thawing garden soil in March here in the Northeast. Worth trying!

Allium species that have not been bred to be commercial crops almost always germinate best with some cold. Occasionally we have lots of Nodding Onion or Tartarian Garlic that germinate easily at room temperature indoors, but more often they benefit from a chill, so we sow them outdoors in early spring, around the time that we are transplanting Onions and Leeks. Red Welsh Onions, especially older seeds, also do well sown into cold spring soil. Leave space to tuck in companions like Nasturtiums or Jewels of Opar later on.

This is obviously not an exhaustive list, but the point is that gardeners should embrace the cold and this fleeting season of transition. We may think mainly of mud and potholes but as the trees and weeds spring to life, so can so many of the seeds you might like to sow but don’t because of the hassle implied in “stratifying”. Just put them outside. And if you’re into this milk jug thing I am seeing everywhere just keep it out of direct sun because those things will heat up like a greenhouse and the whole thing will be for naught. Maybe try a pot.