| Most common germination range | 5–21 days (varies by crop) |
| Standard planting depth rule | 2–3× the seed's diameter |
| Full sun definition | 6+ hours of direct sunlight daily |
| Acceptable germination rate | 70% or higher |
| Typical indoor head-start window | 4–8 weeks before last frost |
Why the Seed Packet Is Your Most Important Garden Tool
Before you buy soil, choose a pot, or dig a single hole, the seed packet already has most of the answers you need. It tells you when to plant, how deep to go, how much space each plant needs, and what growing conditions to expect. The problem is that the terminology can feel like a foreign language to first-time gardeners.
This guide walks you through every common term and number you'll find on a seed packet — in plain English. Whether you're starting tomatoes indoors or scattering wildflower seeds in a raised bed, understanding what you're reading will make a meaningful difference in how your garden grows. If you're just getting started, our beginner's garden overview covers the broader picture of soil, light, and plant selection before you start sowing.
| Most common germination range | 5–21 days (varies by crop) |
| Standard planting depth rule | 2–3× the seed's diameter |
| Full sun definition | 6+ hours of direct sunlight daily |
| Acceptable germination rate | 70% or higher |
| Typical indoor head-start window | 4–8 weeks before last frost |
Decoding the Key Terms and Numbers
Most seed packets share a standard set of labels. Here's what each one actually means:
Days to Germination
This is the number of days you can expect to wait before a sprout breaks through the soil surface. It's usually given as a range (e.g., 7–14 days) because temperature, moisture, and seed freshness all affect timing. If nothing appears by the end of the range, it doesn't always mean failure — some seeds are simply slow.
Days to Maturity
This number tells you how long after germination (or, for transplants, after planting out) the crop will be ready to harvest. It helps you plan backward from your first expected frost date to know whether a plant has enough season to produce.
Planting Depth
Seeds are typically buried at a depth of about two to three times their diameter. The packet will give you a specific number (e.g., ½ inch or 1 inch). Very fine seeds like lettuce or basil are often pressed onto the soil surface and left uncovered.
Spacing
Two numbers usually appear here: the distance between individual seeds or plants within a row, and the distance between rows. Crowding plants reduces air circulation and leads to disease and competition for nutrients. A garden readiness checklist can help you map out your space before seeds go in the ground.
Sun Requirements
You'll see phrases like full sun, partial shade, or full shade. Full sun means at least 6 hours of direct sunlight daily; partial shade means 3–6 hours. Our sunlight reference guide explains how to assess the light conditions in your specific space.
Direct Sow vs. Start Indoors
Some crops (like carrots and beans) dislike having their roots disturbed and should be sown directly where they'll grow. Others (like tomatoes and peppers) benefit from a head start indoors 6–8 weeks before the last frost date. The packet will specify which approach is recommended.
Germination Rate
Often printed as a percentage (e.g., 85%), this figure indicates the proportion of seeds in the packet that are expected to sprout under good conditions. A higher percentage means fewer wasted seeds. Rates below 70% may warrant sowing extra seeds to compensate.
Germination
The process by which a seed sprouts and begins to grow into a seedling. It requires the right combination of moisture, warmth, and sometimes light.
Days to Maturity
The estimated number of days from germination (or transplanting) until a plant produces a harvestable crop. It varies by variety and growing conditions.
Direct Sow
Planting seeds directly into the garden bed where the plant will grow to maturity, rather than starting them in pots indoors first.
Thinning
Removing some seedlings after they sprout so that the remaining plants have enough space, light, and nutrients to grow properly.
Germination Rate
The percentage of seeds in a packet expected to sprout under suitable conditions. It reflects seed quality and storage conditions.
Frost Date
The average date of the last spring frost or first fall frost in a given region. Gardeners use these dates to time planting so crops aren't killed by cold.
Putting It All Together for a Stronger Start
Once you can read a seed packet confidently, you'll find that planning your garden becomes much more intuitive. You'll know which crops need to go in first, which need extra elbow room, and which can handle a shadier corner of the yard.
A few practical habits will help you get the most from this information:
- Keep your packets. Store them in a labeled envelope or small box so you can refer back mid-season.
- Note your local frost dates. The "days to maturity" figure only makes sense when paired with your actual growing window. Your local cooperative extension service (a publicly funded resource available in most U.S. states) can provide frost date averages for your area.
- Don't skip the back of the packet. Most packets print watering notes, thinning instructions, and companion planting tips on the reverse — information often overlooked by beginners.
If your seedlings aren't emerging as expected, this guide to common seedling problems covers the most frequent culprits and what you can do differently next time.
Seed Packets Have an Expiration Date
Most seeds remain viable for 1–4 years when stored in a cool, dry place. Packets typically print a "packed for" or "use by" year. Using old seeds isn't dangerous, but germination rates drop over time. If you're working with seeds from a previous season, sow a few extras to account for reduced viability.