How to read a seed packet and understand its instructions including, days to maturity, hours of sunlight, planting dates, seed depth, and plant spacing.
When I first dove into starting a garden, I was immediately overwhelmed trying to understand when and how to plant everything. I had no clue how to read a seed packet or what any of it meant! Initially, I thought I would buy seeds, and then plant the seeds out in my garden sometime in the spring. I had no idea how to start seeds indoors, what an estimated frost date was, or even what growing zone I was in. If this sounds like you, I recommend starting with my first post in this series, Gardening for Beginners. I cover everything from finding your growing zone, to calculating your first and last frost dates, and even when to plant different types of crops.
Seed starting is a great way to learn more about how plants grow. Buying seedlings ready for transplanting into a garden is very simple and easy, but can also be costly. Additionally, nurseries only offer certain varieties and limited selections. Starting your seeds at home can save you money, allow you to experience new and interesting varieties, and satisfy that craving for gardening toward the end of winter when it’s still too soon to start outside!
General Info or About
Many packets will start with a short paragraph about the type of plant and what you can expect from growing it. This varies throughout different brands. Many will mention if they recommend starting the seeds indoors ahead of your frost date, sowing directions, hours of sunlight recommendation, seed planting depth, or transplanting information. It might also mention how large of a final product you will get from that plant, how big the plant itself will grow, or the amount of produce you can expect to harvest throughout its growing season.
On the front of the packet, you will typically see the common name of the plant followed by the specific variety. This is important to note because different varieties may have different needs when it comes to hours of sunlight or whether they are annual or perennial. Additionally, for example, different varieties of tomatoes may look and taste entirely different from other varieties.
Hybrid or heirloom
There is a lot of debate about which is better, hybrid or heirloom varieties. A hybrid variety has been created by careful selection of plant genetics combined for specific traits like disease resistance. This is a man-made process that must happen in a controlled environment where natural pollination cannot happen. An heirloom variety is one that has been saved for generations with open pollination. Open pollination refers to natural pollination that occurs when bees, insects, wind, or some other natural force moves pollen to pollinate a plant.
Some believe hybrid varieties grow with more success because they are created to tolerate nature’s common issues. However, the seeds from hybrid varieties cannot be saved for true genetics. When you save a seed from a hybrid plant the plant that comes from those saved seeds will not result in the same plant they came from. The seed may also be sterile in some circumstances. Heirloom variety seeds can be saved to grow a true genetic match to the parent plant it was saved from. I tend to grow a mixture of both heirloom and hybrid varieties, its just personal preference.
Days to Maturity or Days to Harvest
Days to Maturity and Days to Harvest can be used interchangeably. It is an estimation of when your plant will be fully matured and you will be able to harvest. This day count is generally taken from when the plant begins growth in the ground. For seedlings started indoors, the count starts when it is appropriate for the seedling to be transplanted outside. For example, a tomato seed will be started indoors about 8 weeks before your last frost date. The eight week old seedling will be transplanted outside after the threat of frost has passed. The days to maturity countdown starts now. For a 120 day variety, it will be 120 days from the day it was transplanted outside until that first fruit is ripe and ready to harvest.
If the plant was not started inside and instead gets planted directly into the soil (referred to as direct sowing), the days to maturity begins after the seedling has emerged from the soil and grows its first true leaves. Of course these are all estimations. Weather or other unforeseen circumstances can alter the actual maturity or harvest date.
Hours of Sunlight
The amount of sun and shade plants receive are crucial to their survival. Some plants thrive in full sun, or more than 6 hours of direct sunlight. Some thrive in partial sun or partial shade which means about three to six hours of direct sunlight. This is extremely important when it comes to plant placement in the garden. If you have an area that is shaded by a large tree for 75% of the day, a plant wanting full sun will not be likely to thrive there.
Seed Depth or Planting Depth
The seed depth recommendation is for how deep to place the seed into the soil for ideal germination rates. A good rule of thumb to follow is that the seed should be planted twice as deep as it is wide. Tiny seeds should be planted very shallow and large seeds can be planted slightly deeper. If you plant a seed too deep, it will not have enough energy or strength stored inside to grow tall enough to emerge from the surface of the soil. Therefore it will never reach light and it will not survive.
Seed Spacing or Row Spacing
Spacing refers to the amount of space between the plants once they are outside in the garden. For example, tomato plants need about one to two sqft feet to spread out and grow, but lettuce can generally be within a couple inches of the next plant and still have plenty of room to grow.
Days to Germinate
Germination is different for almost every plant. For example, some peppers can take up to three weeks to germinate. This means that from the time you place the seed into the soil, it could take three weeks for the seedling to pop out of the seed and begin growing. This is important when assessing your germination rate, or the percentage of seeds that turned into seedlings. If you assess too early, your rate may be low when you just need to wait a few more days. Also note, some seed packets will indicate how many days before “seedlings emerge”. This is another way of saying the days to germinate.
When a packet lists information that starts with the phrase “start indoors” it is recommended that you plant that seed inside a controlled environment a certain number of weeks before your last expected frost, where frost is not a concern. This is for crops that have long growth cycles and benefit from a jump start on the growing season. This is particularly important if you live in a northern climate and have a short growing season. Your growing season is the amount of days between your last frost in spring and the first frost in fall. For example, many tomatoes have around 120 days to maturity but also suggest starting indoors 8-10 weeks before the last frost. If you wait to plant those seeds directly in the soil after the threat of frost, you may miss out on an extensive harvest season.
Some crops are best started directly in the garden soil after the threat of frost has passed. This is referred to as direct sowing, or placing the seed in the ground to grow outside. These are typically crops with shorter growing cycles that mature quickly. Additionally the root systems of these crops do not tolerate being up-potted or transplanted into the ground. Direct sowing eliminates the risk of damaging their roots.
A recommendation for thinning refers to removing seedlings that have emerged too close together to foster proper growth. As mentioned earlier, it’s important to give plants the right amount of space that they will need as they grow. Obviously a seedling is much smaller than the plant at full development. When plants are overcrowded, they end up “fighting” for nutrients in the soil, sunlight, or water and all plants suffer.
Packed for Date or Sell by Date
The date listed on seed packets is not an expiration date! Seeds do not expire! If your seeds are stored properly (cool, dark, dry), they will keep for many years. However, the germination rate tends to go down for seeds the longer they sit around. This just means, if you have older seeds, start a couple more than you want because they may not all germinate and become seedlings. Manufactures are required to label their packets with the date of the year they are packed in. DON’T throw away seeds! Just give them a try because you have a 100% chance of them not growing if you don’t plant them!
Things to remember
Seeds want to grow. Seeds are created for the biological purpose of growing into a plant that produces a fruit, leaf, root, or flower. Yes, the above list seems like a lot to learn and understand but, seeds have simple needs. They need warmth, water, and sunlight. Don’t over complicate it for yourself and don’t let the long lists scare you away from starting your own plants from seed. It is truly the most rewarding feeling to grow something all the way through to harvest. Give it a try and see what happens! You may surprise yourself with what you can grow.
I hope this helps with how to read a seed packet and gives you the confidence to grow some plants from seed! If you are just getting started learning about gardening, I highly recommend my post Gardening for Beginners. Lastly, make sure to check back for the next post in my gardening series all about starting seeds indoors and the supplies needed!
I hope you enjoyed this peek into Life at Metzger Acres!