Saturday, January 12, 2013

Read it and reap

A seed catalog is a rich harvest of information for gardeners of all levels. Here's how to read one.

Karen Hager is The Roanoke Times' gardening columnist. Her column appears twice monthly in Extra.

Recent columns


About Karen

Karen Hager lives in Blacksburg with her garden-loving family: a husband and son. She learned her skills by trial and error, and encourages all gardeners to do the same. You can reach her at

For gardeners, January can only mean one thing: the new seed catalogs have arrived.

With few other outlets available to indulge your gardening needs, nothing beats curling up on a cold winter day and planning your upcoming garden.

Good seed catalogs contain so much information that experienced gardeners often refer back to them throughout the growing season. For novice gardeners, the choices can be daunting and sometimes downright confusing.

Here is a primer on reading a seed catalog.


Commercial growers and home gardeners are interested in different attributes and likely will purchase different seeds. The commercial grower may need to ship food across the country, so storage attributes are a major concern. Home gardeners just need to get produce from the garden to the table.

Search out seeds that fulfill your needs. If you want to can or freeze beans, look for a variety where the description touts the plant's ability to can or freeze well.

If you're buying pumpkin seeds, your needs will determine the variety of seed to choose. For pumpkins, it's often a choice between size and taste. Atlantic Giant grows pumpkins that weigh 200 pounds, but that would be a poor choice if you want to grow pumpkins for pie.

As you read descriptions, know that what isn't said is just as important as what is said.

If you're buying tomato seeds, for example, flavor is likely to be your main concern. If the description of a tomato seed doesn't prominently mention flavor, and instead emphasizes size, color, yield or some other quality, be wary.

Weather factors

A major factor in choosing seeds is whether or not the plant is appropriate for growing in this area.

Depending on where you live, you are likely to be in hardiness zone 6 or 7. Hardiness zones are based on average minimum temperatures in the area, and a growing zone map is usually in your seed catalog. The Virginia Cooperative Extension ( can help you to define your zone even more precisely.

Seed descriptions will also include information about frost tolerance and resistance to bolting. If you want to grow something that's a bit out of season, look for varieties that can withstand the temperature variance.

For example, lettuce is a cool-weather crop that bolts when the weather turns warm, but it is possible to choose a heat-tolerant variety that will mature during the summer.

Light requirements

A seed catalog will usually display icons of the sun with the center clear, half-black or entirely black. This icon indicates how much light the plant will need to grow.

An open, clear center means that a plant requires full sun, defined as six or more hours of direct sunlight each day. A half-black center means that partial sun is required, defined as three or more hours of direct sunlight each day. A black center means that the plant grows best in the shade.

Almost all vegetables, fruits and herbs require full sun. Lettuce, green beans and a few herbs will grow in partial shade, but none will grow in full shade.

Days to maturity

This refers to the length of time required for the plant to go from seed sowing to harvest. For long-season crops that are traditionally started indoors, this number is calculated from transplant date, rather than sowing date. Be sure you know which starting point is used by your catalog.

Days to maturity dates become helpful as you plan planting and harvesting schedules.

Remember that this date is an estimate, and may vary with your particular experience.

Disease tolerance and resistance

The more resistant or tolerant a plant is to disease, the less likely disease will ruin your crop.

When a plant is listed as "disease tolerant," the plant may contract a particular disease, but it probably will not be so bad that it will adversely affect the appearance or harvest.

For seeds that are "disease resistant," the plant has been bred to resist common diseases and will likely not get the disease at all.

Once you narrow down your seed choices, disease resistance and tolerance are good qualities to examine.

Cracking the codes

As you peruse your seed catalog, you'll notice two common codes: OP and F1.

OP refers to open-pollinated varieties, which means that the seed is genetically stable and will produce offspring very similar to the parents. Heirloom varieties are open-pollinated. These are the types of seeds that are fine to collect at the end of the season to use for future years.

F1 varieties are hybrids, produced by crossing two genetically different, but related, plants to produce offspring that has increased yield, vigor or some other particular attribute. The plants produced often outperform open-pollinated varieties in a particular way. The downside is that the better performance only lasts one generation. If you collect seeds from these plants, the offspring is likely to be weak and inferior to the parent.

You may also see other letters after the names of varieties, and these also indicate a hybrid seed.

You may see designations for award winners, too. AAS designates the plant as an All-America Selection Winner, from a nonprofit gardening organization that recognizes varieties for superior qualities. PPA is a Perennial Plant Association winner, which recognizes varieties that have been grown in U.S. trial gardens and shown to be outstanding performers.

Join the gardening conversation on my blog at for another opportunity to indulge your gardening whims in the winter.

Karen Hager's column runs every other Saturday in Extra.

Weather Journal

News tips, photos and feedback?
Sign up for free daily news by email