Save Tomato and Bean Seed First and Leave the Squash Alone

Quick answer: Start with open-pollinated tomatoes, beans, peas, lettuce and peppers. Skip anything marked F1, and leave squash and corn alone until you've got a season of seed saving behind you.

The best tomato in your garden this year is the one you shouldn't eat.

That's most of the discipline. You walk past the biggest, earliest, best-tasting fruit on your healthiest plant and let it go dead ripe for the seed jar. Everything else is technique, and the technique is cheap. Coffee filters, a few mason jars, some envelopes and the silica gel packets you've been throwing out of shoeboxes. You probably own the whole kit already.

Check the packet before you save anything

Dig out the seed packets from spring. If you see F1 or "hybrid," that plant's seed won't give you the same plant next year. A Sun Gold cherry tomato is a hybrid. Save its seed and you'll get something, but it might be bigger, sourer, a different color, or later. A hybrid's kids are a coin toss.

"Open-pollinated" and "heirloom" are what you want. Brandywine, Cherokee Purple and Kentucky Wonder pole beans all come back true from saved seed, provided nothing crossed with them.

A concession, because it's real: hybrids aren't the enemy. Plenty were bred for disease resistance you'll miss in a wet August. If you love one, buy it again next spring and save seed from your heirlooms. This isn't a purity contest.

A few modern varieties also carry patents that restrict saving. The packet will say so. Read it.

The easy five, and why they're easy

These crops mostly pollinate themselves inside a closed flower, so your neighbor's garden doesn't get a vote.

• Tomatoes. Modern varieties rarely cross. Give different varieties about ten feet and you're fine. Potato-leaf heirlooms and tiny currant tomatoes have more open flowers, so give them extra room.
• Beans. Self-pollinating. Ten feet or so between varieties is plenty for a backyard.
• Peas. Barely ever cross. Easiest seed you'll save.
• Lettuce. Self-pollinating, but it takes its time. More on that below.
• Peppers. The one on this list that'll surprise you. Bees do cross peppers, more than people expect. Plant a habanero next to a bell, save the bell's seed, and next year somebody bites into a pepper popper and loses his composure. If you grow hot and sweet together, slip a small mesh drawstring bag over a few unopened flower clusters and leave it until the fruit sets. Save seed only from those.

Why squash will make a fool of you

You grow one perfect zucchini plant. You save seed from a fat, healthy fruit. Next July, you get a pale, striped thing shaped like a football with a neck.

Your neighbor two yards over grew jack-o'-lanterns. Most zucchini, yellow squash, acorn squash, delicata and a lot of pumpkins are the same species, Cucurbita pepo, and bees carry pollen between them without asking anybody. Seed savers who care about purity want those varieties a half mile apart or more. In a subdivision that's not happening.

The workaround is hand-pollination. Move pollen from a male flower to a female one yourself, then tape the female flower shut so no bee gets in after you. If you've never done it, start with why your zucchini rots before it grows, which walks through male and female flowers. Doable, fussy, and not a first-year project.

Two more to skip for now:

Corn pollinates by wind, crosses across long distances, and needs a lot of plants in the patch to keep the line healthy. A backyard block of twenty stalks won't do it.

Carrots, beets, onions and cabbage are biennials. They don't make seed until their second year, which means overwintering them in the ground or in storage and replanting. Carrots will also cross with Queen Anne's lace, the roadside weed. Save that for year three.

How to do it, crop by crop

Tomatoes: let it rot on purpose

Pick a fully ripe fruit, ideally one from each of two or three of your best plants. Cut it across the middle and squeeze the seeds and gel into a jar. Add about the same amount of water. Label the jar right away, because in two days every jar looks the same.

Leave it at room temperature for two to four days. It'll stink. A gray-white mold will grow on top. That's what you want. The fermentation breaks down the gel around each seed that keeps it from sprouting, and it knocks back some seed-borne disease.

When the mold's covered the surface, add water and stir. Good seeds sink. Pour off the mold, the floaters and the pulp. Rinse what's left in a fine strainer.

Spread the seeds on a ceramic plate or a coffee filter. Not a paper towel. The seeds glue themselves to it and you'll spend February picking lint off them. Let them dry for at least a week, stirring once a day so they don't clump.

Beans and peas: wait for the rattle

Leave the pods on the plant until they're brown, papery, and rattle when you shake them. That's later than feels right. If frost or a week of rain is coming, pull the whole plant and hang it upside down in the garage to finish.

Shell them and run the bite test. A dry bean won't dent under your teeth. If you're not keen on biting it, tap one with a hammer. It should shatter, not squish.

Peppers: let them go past pretty

Leave the fruit until it's fully mature color, usually red, and starting to wrinkle. Cut it open, scrape the seeds onto a plate, and dry them the same way as tomatoes, no fermenting needed. Wear gloves for hot peppers. You'll rub your eye eventually. Everybody does.

Lettuce: save from the stubborn one

Lettuce bolts in heat and sends up a tall flower stalk. Don't save seed from the first plant to bolt. You'll be breeding a lettuce that quits early. Save from the last one standing. When the heads turn fluffy like dandelions, bend the stalk into a paper bag and shake.

Your zone decides where it goes wrong

In short-season country, zones 3 through 5, frost is the problem. Seed has to mature before the first hard freeze, and a long-season heirloom may not get there. Save seed from your earliest varieties first, plant your seed rows of beans early, and be ready to pull plants and hang them indoors.

In the humid South, zones 8 through 10, drying is the fight. Seed that sits damp loses vigor fast. Dry indoors with the AC running or a box fan on low, never on a screened porch in July.

If you're not sure which you're dealing with, your hardiness zone decides a lot more than what survives winter.

Storage is where most saved seed actually dies

Old seed-bank rule of thumb: the temperature in Fahrenheit plus the relative humidity percentage should add up to less than 100. A garage in Houston in August fails that test by a mile. The back of your refrigerator passes it easily.

• Put each variety in a paper envelope. Write the name, the year, and which plant it came from.
• Put the envelopes in a mason jar with a silica gel packet or two.
• Keep the jar in the fridge, or the freezer if the seed is bone-dry.
• Out of the freezer, let the jar warm to room temperature before you open it, or condensation forms right on the seed.

Shelf life varies. Onion and parsnip seed fades within a year or two. Lettuce and peppers last a few years. Tomatoes and beans hold up for several. Write the year down and you won't have to guess.

Test it in February

Count out ten seeds, fold them into a damp paper towel, slip it into a zip bag and set it somewhere warm. Check after a week or ten days. Eight sprouts means 80 percent germination. Fewer than five, sow thick or buy fresh.

Then start them under lights. Starting seeds indoors is where saved seed earns its keep.

Give more back than you got

You'll end up with far more seed than one garden can use. A single tomato hands you enough for a neighborhood. Fill a few labeled envelopes for the family next door. A lot of public libraries now run seed libraries, so drop some there too.

And if an old-timer gave you his heirloom beans, bring him back a full jar in the fall, cleaner and drier than the handful he gave you.

Every heirloom you've ever eaten exists because somebody walked past his best tomato. This year it's your turn.