How To Read Seed Packets

By: Dr. Leonard Perry, Extension Professor
University of Vermont

The colorful pictures and fanciful names on the seed packets at your garden center and in seed catalogs entice you to buy.  But before you get carried away and select more varieties than you have space to plant, take a minute to read the packets and descriptions. There is much good cultural information in these, some of which may be unclear if you are new to gardening.

You may be surprised to learn that some of the flower and vegetable varieties for sale are not well suited to your particular location.  Some grow best in a certain type of soil or shade conditions, or need to be started indoors well in advance of planting. Start them too late, or just sown out in the garden, and you may get few if any flowers or fruit this season. So what do you look for on the packets and in catalog descriptions?

VARIETY– Most packets and descriptions list the name of the variety (technically most are cultivars or cultivated varieties), and tell you if it is a hybrid.   Hybrids come about from the crossing of other plant parents, and are often denoted as F1 or F2.  This often gives a trait such as bigger flowers or more vigor.  It is important to know if you want such traits, or if you want to collect seeds.  If you collect seeds from a hybrid, they won’t make the same plants.  For this you would need the parent plants (often a seed company trade secret).  To collect seeds that will come “true”, you should look for “open pollinated” varieties.

TYPE– Flowers also are identified as annuals, biennials, or perennials.  Annuals are plants that grow, bloom, and die in one growing season.  Biennials bloom the second year after planting and generally die after flowering.  Perennials are those plants which come up year after year (if they are hardy).  For perennials, many descriptions have or refer to a hardiness zone map so you can see if the plants will have a chance in your area.

DATE–For best results, buy only seed that is packed for the current year.  The date is generally stamped on the back flap.  Although you might be able to find seeds packaged for last year at a discounted price, these are probably not a good buy.  Poor storage conditions will reduce the viability of seeds.  If you do want to take a chance on these, sow 10 seeds in moist, rolled paper towel to see how many germinate.

GERMINATION–This percentage tells you how many seeds will produce plants under ideal conditions.  However, keep in mind that the age of the seeds, how they’ve been stored, as well as how and when you plant them also will affect germination.  Some seeds may need exposure to light to germinate.  Some perennials may need special seed treatments prior to sowing.   If you start seeds indoors in flats under ideal conditions, count on a slightly higher germination rate than if sowing directly outdoors. Descriptions often tell you which is best.

CULTURE– Most seed packets will contain information on how and when to plant, including the number of days to seed germination, and days to harvest for vegetables. Make sure if you see days listed that you know what they refer to—days from sowing to harvest, from planting out to harvest, or other. Packets also will note spacing requirements, height and spread at maturity, thinning instructions, growth habit, and special cultural considerations.

NUMBER OF SEEDS– Unless you are buying bulk seeds by weight, you can be misled by the size and shape of the packaging.  Be sure to check the weight, or more often number of seeds, to determine how much to buy.  This is particularly important with higher priced seeds like geraniums that may only have five to ten seeds per packet. Some descriptions provide information on the length of row the packet will plant.

DESCRIPTION—Some parts of the plant description that may be important to you are whether the seeds are organic.  If a vegetable, what are characteristics and shape and size and taste of the fruit?  Is this variety resistant to diseases?  This is especially important for some vegetables such as tomatoes, melons, and squash. Often specific diseases are listed with letters which can be found in a key or bottom of the page, such as “V” for verticillium disease resistance.

You may see logos with descriptions.  These should have a key if in a catalog, often for such as easy, organic, new, or an award winner.  The most common award you will see for some is the shield of All-America Selections winners.  These are varieties that have proven among the best in certain regions, or nationwide, and can be found online (www.all-americaselections.org/).

Also in descriptions, as in ads for other products, look for what “isn’t” said.  In other words, if you want a trait such as good freezing for beans and this isn’t mentioned, this variety likely won’t freeze as well as others.  On the other hand, be wary of glowing descriptions such as “the best taste in our trials”.  Often I find most varieties offer the same superlatives, and what tastes good to one person isn’t as good to another.  Look for traits that are most important to you, such as size of fruit, color of fruit or flowers, height of plant, the need or not for staking, yield, or time of flowering or ripening.  While flavor is often the most desired trait of vegetables, color is often the most desired trait with flowers.

It bears repeating to have some sort of plan, or at least know how much space or how many pots you have, before buying seeds.  It is so easy (speaking from experience) to be enticed by all the different varieties with colorful photos and glowing descriptions, ending up with several times as many seeds as you have the time or space to plant.

4/1/14

Distribution of this release is made possible by University of Vermont Extension and New England Grows–a conference providing education for industry professionals and support for Extension’s outreach efforts in horticulture.