How to Read a Seed Packet
Seed packets have tons of useful information and it is important to look at all the information over just a pretty picture. Pretty much all seed packets will have the following information on them. Reading seed packets not only helps you become a better gardener but it will also help you learn about the different vegetables and varieties that you grow.
First when you are planting your seeds make sure to hold onto your seed packet! It is very easy to forget which of your varieties did great and which didn’t (drawing a quick little map of your growing area also helps).
Days to Maturity
This is the time from germination to when you can harvest from the plant. These can range quite a bit between different varieties. This is an important measure when thinking about the timing of your garden. If you are planting cool-season plants a little later than you should, looking for plants and varieties that have short days to maturity (DTM) is ideal.
Germination/Days to Emergence
On the back of most seed packets you will see germination or days to emergence window. This ranges from a few days to up to 30 days depending on your vegetables. This is very helpful when figuring out if some of your seeds didn’t germinate. Remember this is an estimate based on ideal conditions. Make sure to read the planting directions.
Seed Depth
Some seed packets will have seed depth but if yours doesn’t the rule of thumb is to plant no deeper than twice a seed’s diameter. This will range from planting seeds on top of moist soil to about 1 inch in depth. It is always better to lean towards planting too shallow than too deep.
Spacing/Thin to
Packets will often provide how far apart to place seeds as spacing but occasionally they will phrase it as “thin too”. Whenever planting seeds it’s best to plant 2-3 seeds per recommended spacing and then once the “true” leaves appear to thin them to 1 plant using a pair of scissors (don’t pull them out).
How to Plant
This information is usually separate from the spacing, emergence, and depth information. It is often in more of a paragraph on the back of the seed packet. It is very important to read this information. It will let you know if you can plant these outdoors, have to start them inside, or if you have to do more advanced techniques such as soaking, cold stratifying, or scaring the seeds.
When to Plant
This information is usually nearby the How to Plant information. It is always based on the first and last frost dates of the year. It will often say things such as “after danger of frost, sow outdoors” or “4 weeks before the last frost date”.
You can also use a planting calendar to help with figuring out when to start planting.
Expiration date
Every seed packet has an expiration date similar to how food has expiration dates. Often they are set to expire about 1 year after being packed. The expiration date on the packet has little to do with the actual expiration of the seeds. Most seeds when kept in a cool dry place can last years without losing much germination. Even with seeds that have been expired for years, it is often that only 5-15% of the seeds will not germinate. So if you are using seeds that are a few years expired, don’t throw them, just throw a few extra seeds to guarantee germination.
Variety Description
Often seed packets will also have a description of the seed variety it contains. This is like the sales pitch for what makes this variety different from any other variety of that crop. This is where you will learn if the variety is more resistant to pest or disease, more heat or cold tolerant, faster growing, or other things that would make it unique in comparison to other varieties. Although this section can be very helpful and important it is also vital to know what standard they are using as a comparison. As an example we were looking at a variety the other day and at first were excited because it claimed to be very cold tolerant. Then we read the rest of the description where it said something along the lines of “this super cold tolerant variety even survives when we have one of our big winter storms where temperatures can plunge below….20F.” So just because something is considered cold tolerant somewhere else doesn’t mean it will survive our cold here. This can also be the case with disease resistance. If a variety claims to be very resistant to fungal diseases but the seed company you are getting it from is in the southwest where it’s dry and isn’t very humid (aka there isn’t much fungal disease to begin with) it might still get fungal disease here.