Are you thinking of saving some seeds? The best time to start is early, so that you can get your garden planned and planted for success. Below, you will find tips for planning and planting your seed garden.
1. Get Enough Sun
Most plants prefer full sun to make good quality seeds. That's because plants are solar-powered, so they grow to maturity faster and stronger when they get lots of sunlight.
In a city garden it can be challenging to find sunny places among the trees and buildings, so gardeners often grow leafy plants like lettuce and spinach in shade or partial shade, because they can tolerate less sunlight. The reason for this: plants need more energy to produce fruit and seeds than they do for leaves. This is why many plants can survive in shady places, but will not bloom.
That's a fine strategy for growing the greens, but it probably won't work if you're looking to save the seeds from your leafy greens, so you'll have to plan ahead to find a spot that receives enough sunlight.
If you want your seeds to be "true to type", which means they will grow the same as the plants they came from, you have to prevent them from being cross-pollinated with other varieties.
Learn which plants cross with each (e.g. pumpkins cross with zucchini, but not with watermelons) and how far apart you should plant them to limit their crossing. Also keep in mind what your neighbours are planting and how far away their gardens are.
If in doubt, there are many references for isolation, including our book, 'How to Save Your Own Seeds'. The easiest vegetables from small garden seed saving are: tomatoes, beans, peas, and lettuce. We recommend at least 3 meters (about 10 feet) of space between different varieties for home seed saving. For commercial seed saving, the distance would need to be larger.
3. Leave Extra Space
Many gardeners are accustomed to planting greens close together since they're normally harvested before they grow large and crowing tends to prevent them from growing too large. But if you're growing the plants to seed, they need lots of space to grow fully, make flowers, and form seeds.
Leave at least a full foot of space around of lettuce plant (and remembers that they'll grow to be 3 - 4 feet tall, and up to a foot wide at the base).
A great strategy is to plant lettuce and other greens closely, but when harvesting, leave on in the ground at every food, to grow to seed. That way, there's plenty for eating and for seed saving.
4. Leave Extra Time
You harvest tomato seeds from ripe tomatoes, and pumpkin seeds from ripe pumpkins. But keep in mind that seeds for lettuce, cucumber, broccoli, zucchini, radishes, all biennial vegetables, and anything that gets eaten before it bears seeds, will need more time to grow than what most people are used to.
Depending on the variety and your climate, you might want to start most seeds indoors so they have a good chance of seeding during the drier part of late summer.
5. Don't Baby Your Seed Crop
You want all your plants to grow perfectly, but there's always that corner of the garden where the soil is crustier and the lettuce always bolts. Use this to your seed saving advantage!
Every gardener learns to keep their lettuce tender, their radishes mild, and mustard greens lush by giving plenty of water, rich soil, and lots of tender loving care. All of this is in an effort to keep plants from going to seed.
Take nature's hint and let your seed crops struggle a little bit by paying less attention to them and by watering only when necessary. You'll get more seeds and they'll ripen earlier.
6. Plan Succession with Seed Harvests in Mind
It's good to plan for how to rotate planting during the season.
If you normally plant radishes in spring, harvest them with a month and re-sow that space with green bush beans (a smart plan if you're a non-seed-saver), you'll have to change that plan if you're growing the radishes for seeds because they'll need half the summer to mature.
Maybe you don't need the whole row for seed. Leave one end to sow seeds, and harvest the rest for eating. Then re-sow the harvested part with short-season spinach that will finish at about the same time as the radishes go to seed.
You could end up with a more complicated garden, part-rows maturing at different times, but that tends to happen throughout the season, anyway, so there's no need to avoid it so long as you keep track of what's going on.
7. Sow Biennials Later in the Season
Many biennial vegetables, such as beets, carrots, turnips, and cabbage can handle some frost, so it's common to plant them early in the spring. That's excellent is the plan is to eat them, because you get a longer season of produce. But if it's seeds you're after, sow the seeds a little later in the season - about 70 days before the end of the season. The reason: smaller roots often store better over winter than large ones.