At the end of summer, I look over my crops and make an assessment of their productivity through the seasons. Okra, tomatoes, cucumbers, squash and other crops may no longer be the thriving, compact plants they were a few months ago — but they're hanging on, battered and brown in some areas, still yielding harvest each day.

At this time of year, it's clear to see which crop varieties have done well and which have not. Late freezes in the spring were too much for Lady Finger okra. Several varieties of tomatoes I planted stopped producing fruit after May. Delicious 51 cantaloupes tied me down with demanding watering needs, then turned out small, tasteless melons hardly worth my effort.

On the other hand, Texas Wild and Nichol's Estate tomatoes were outstanding performers, as were Clemson spineless okra, Israeli melons, Danvers 126 carrots and cocozelle zucchini. I was especially pleased with the drought-tolerance of a single Punta Banda tomato plant that returned to life after nearly dying from lack of water. It continues to hand over delicious fruit, with no signs of slowing down.

My final assessment will help me make better use of my garden space next year, by replanting what works well and tossing out what doesn't. It also gives me insight into which crops may be good candidates to improve through the art of seed saving.

Who gets picked
Saving the seed from this year's harvest to plant next year not only saves money, but it also adapts each variety to the soil and climate where the seed is planted. For example: A drought-tolerant tomato from Arizona that grows moderately well in Texas can be made to grow even better simply by gathering seed from the healthiest plants each year and planting them the next. Gardeners who do this are assisting natural selection, furthering along the plants that show off the best genes.

As for which seeds to collect: First, the plants must be open-pollinated — no hybrids or genetically engineered organisms. Most transplants sold at the home improvement stores are hybrids. Avoid those, as they'll produce unpredictable seeds.

Second, during planting season, you want to maintain a distance between plants of the same type. Otherwise they'll cross-pollinate, which can also result in unpredictable seeds. Seed producers keep a mile between varieties; for the backyard gardener or small-scale farmer, several car lengths is enough space.

That said, cross-pollination can be useful, creating some amazing blends, but they won't exhibit traits consistent with the original seed. The new traits can be delicious, or they can be a step in the wrong direction. It's a gamble. Gambling can be fun. There are always the good seed companies to keep the lines pure if you fail.

Every seed you take
For almost every crop, saving the seed is simply a matter of letting it dry out on the plant or sit in overripe fruit for a day or two; extracting it; drying it; and storing it in an unsealed container or paper bag in a cool, dark shelf in the cupboard.

For vegetables with seeds in pods, such as okra, beans and peas, we let the pods dry out until the seed turns hard and is easily cracked out. For corn, we let the kernels harden and the husks dry out. Then the kernels can be picked off with ease and packed away in an envelope.

For peppers, melons and cucumbers, we let the fruit over-ripen before we extract the seeds and dry them out on a plate.

For carrots, Swiss chard, kale, collard greens and herbs, we keep plants healthy long enough so that they produce flowers. Once the flowers fade and drop off, they leave behind clusters of seeds in their place. Each plant is loaded down with enough to make dozens of seed packets.

Then there is the tomato
The tomato is the most complicated plant for harvesting seed, with many steps. And yet success is nearly guaranteed, which illustrates just how easy seed saving can be. Furthermore, tomatoes are self-pollinating — no insect required — so the seed that each plant produces is more predictable.

First, I cull out the healthiest plants and gather several overripe tomatoes from each. Then I cut each tomato and squeeze out the meat, juice and seed into a bowl. Once I've finished squeezing it all out, I add water to the juicy clumps in the bowl so that the amount is about doubled.

Tomato seed is prevented from sprouting inside the tomato by a compound in the fruit that inhibits seed germination. To remove that compound from the seed, you leave the clumpy seed mix out at room temperature for as long as it takes for a white mold to form a skin across the top.

Once the mold forms, you skim it and the fleshy tomato meat out of the water. It's usually easy; if not, whisk the mix until the meat and the seeds separate and the seed settles to the bottom of the bowl.

The final step is to run clean water over the seed in a strainer. I use a wire mesh sink strainer for this step. I don't aim to eliminate every last trace of the tomato skin or flesh; there will be a few specks that aren't worth the effort to extract.

Then I set the strainer aside for a day in the open air until the seed dries. I pack up the seed in an envelope sent generously to me by a soliciting credit card company, label it and set it aside for next year.

With no practice, skill or supervision, I mastered tomato seed saving the first time I tried it in my late 20s, even leaving the mix to ferment and grow mold. I didn't know to let it mold; it was just one of those happy coincidences that happens for procrastinators and semi-lazy people like me. My experience shows how the art of seed saving is almost instinctive.

I enjoy knowing how to save seed. It allows me to try more varieties each season without increasing my garden budget. Seed saving is also my means to secure access to the varieties of garden plants I've come to depend on.

I enjoy patronizing seed companies that engage in sustainable practices. But who knows if they will always be in business? Or perhaps drop a variety, as one company did some years ago with a seed called Five Color Silver Beet. The only reason this beautiful array of red, orange, purple and white Swiss chard can still be found today is because gardeners held onto it year after year and kept the variety alive.

If not for the efforts of seed savers who master the techniques of cultivating and harvesting crops in backyards or open fields, we'd have fewer options for our gardens and dinner plates.

Dried okra pods with okra seeds ready to crack out of their natural containers.

Photo by Marshall Hinsley

Dried okra pods with okra seeds ready to crack out of their natural containers.