So many wonderful small seed companies, so little space. And don’t forget that in this age of texting, Twittering, and blogs, there still are small companies that don’t offer their wares online.

You can find them many of them using Google, but ordering will require a postage stamp.There are three ways to ensure immortality, the saying goes: Have a child, write a book, or plant a tree.

Those who choose No. 3 — and have the patience of Job — should start with the Schumacher Co., a candy store for Johnny Appleseed wannabes. There are half a thousand tree choices available by the ounce or by the pound. Peruse the catalog carefully, perhaps beginning with the 47 maples, because you’re planting for posterity.

Totally Tomatoes The tomato’s reputation as an aphrodisiac may explain why so many sellers are devoted to America’s favorite fruit/vegetable. There are hundreds of “love apples” to try, everything from grape-size tidbits to 2-pound clunkers, and colored — either skin or flesh or both — white, yellow, green, orange, pink, purple, brown, black, and the customary red. Bicolors, too, such as ‘Green Zebra,' ‘Schimmeig Creg,’ ‘Vintage Wine,’ and ‘Georgia Streak,’ perfect for gardeners who can’t settle on a single hue.

Southern Exposure Seed Exchange Located a stone’s throw from Jefferson’s Monticello, SESE’s long suit is varieties adapted to the Mid-Atlantic region — you can find natural colored cottons and a dozen lima beans — but there is bounty enough to keep gardeners happy no matter what their location. Open-pollinated edibles are the heart of SESE: It was among the first to offer the legendary tomato ‘Radiator Charlie's Mortgage Lifter.’ But SESE is no horticultural Luddite — it also offers a disease-resistant ‘Mortgage Lifter’.

Cheap Seeds Not the most elegant company name, but good flower seeds — annuals and perennials — at very good prices. You won’t find the latest cultivars at this floral emporium, but all the standard names are present and accounted for, African daisies to zinnias. Most packets contain enough seeds to fill the neighbors’ beds and borders as well as your own. Gardeners with far-flung acreage can buy by the pound: $50 for a pound of black-eyed Susan seeds, if you’re up to tending 1,7000,000 seedlings.

Willhite Seed, Inc. It was “watermelons only” when T.A. Willhite began selling seeds a century ago. The company now embraces flowers, herbs, and vegetables — F1 hybrids as well as dependable older varieties — but its heart still belongs to Citrullus lanatus. You can pick from more than 50 open-pollinated and hybrid varieties: reds, yellows, and oranges; seeded and seedless; even melons weighing 100 pounds and more, a perfect fruit for an outfit in Texas, where bigger is always better.

Companion Plants Now in its 28th year, this Ohio firm offers both plants and seeds for more than 200 common and exotic herbs, Achillea filipendulina to Withiana somnifera.Dyers, sachet-stuffers, and wreath- and arrangement-makers will find plenty to like in this herbal manifest, as will bees and butterflies and cooks, even gardeners seeking plants to repel insects and other pests.

Field & Forest Products and Mushroompeople It’s spawn, not seeds, from these firms, which can fulfill the fungi fancier’s every desire: mycelial tissue for maitakes, morels, reishis, wine caps, and oysters, as well as “common varieties” such as white buttons, criminis, and portabellas. There also are books and cultivation tools for mushroom-growing beginners, but you’ll have to supply the hardwood logs if you want to produce a crop of shiitakes.

All the familiar Asian vegetables are here — Chinese cabbage, snow peas, daikons — but so are a wokful of less-known plants, such as tong qwa, poha berry, mibuna, misome, and komatsuna. Altogether there are several hundred vegetables, herbs, and edible flowers to choose from — and both firms offer either cookbooks or recipes so you can turn your daikons into Auntie Betty's takuan tsukemono or your mizuna and nappa into shabu-shabu.

The Fragrant Path Even the odoriferously challenged will find something to sniff in this seed list, a redolent collection of hundreds of “fragrant, rare, and old-fashioned plants” selected by Ed Rasmussen, a Nebraskan with a nose for more than the news. Sweet peas, which reveal their fragrance in their species name odoratus, are an expected favorite with customers, but there even are grasses worth sniffing.