Why Reading a Seed Packet Matters
That small envelope holds more than just seeds — it holds a blueprint for growing success. Most gardeners glance at the picture and toss the packet aside, but the fine print on seed packaging contains critical information that can make or break your growing season. Let's decode it section by section.
Key Information Found on Every Seed Packet
1. Days to Germination
This tells you how long it typically takes for a seed to sprout after planting under ideal conditions. It is usually expressed as a range (e.g., 7–14 days). If nothing has sprouted by the end of the range, the seeds may be old, planted too deep, or the soil temperature may be off.
2. Days to Maturity
This is the number of days from transplanting (or sometimes from direct sowing) until the plant produces harvestable fruit or flowers. Use this to plan backwards from your first expected frost date. If a tomato variety says 85 days to maturity, count back 85 days from your frost date to find your latest planting window.
3. Planting Depth
Seeds are sensitive to depth. A general rule is to plant seeds at a depth of two to three times their diameter. The packet will specify the exact recommendation. Planting too deep can prevent germination; too shallow can dry seeds out.
4. Spacing Requirements
Seed packets list both in-row spacing (between plants) and row spacing (between rows). Overcrowding leads to competition for water, light, and nutrients. Always follow these guidelines — it's tempting to pack plants in, but you'll regret it come midsummer.
5. Sun Requirements
Look for one of these three designations:
- Full Sun — 6 or more hours of direct sunlight per day
- Partial Sun / Partial Shade — 3 to 6 hours of direct sunlight
- Full Shade — fewer than 3 hours of direct sunlight
6. Hardiness Zone or Planting Season
Many packets reference USDA Hardiness Zones or indicate whether the plant is suited to cool or warm seasons. Cross-reference this with your local zone to determine if a variety is appropriate for your climate.
7. Seed Count vs. Net Weight
Some packets list the number of seeds; others list weight in grams. Both are useful for calculating how much ground you can cover and whether a packet represents good value.
Understanding Seed Type Labels
| Label | What It Means |
|---|---|
| Open-Pollinated (OP) | Seeds that breed true — you can save seeds for next year |
| Heirloom | Open-pollinated varieties with a history of at least 50 years |
| Hybrid (F1) | Bred for specific traits; seeds don't reliably breed true |
| Organic | Grown without synthetic pesticides or fertilizers |
| Treated | Coated with fungicide or pesticide — not suitable for organic growing |
Don't Ignore the "Packed For" Date
Seed viability decreases over time. The "packed for" date tells you the year the seeds were intended to be sold. While many seeds remain viable for several years when stored properly, older seeds may have lower germination rates. As a rule of thumb, do a germination test on any seeds more than two years old before committing them to your garden beds.
Quick Checklist Before You Buy
- Is the variety suited to your climate zone?
- Do you have the right sun exposure?
- Does the days-to-maturity fit your growing season?
- Is the seed type (heirloom, hybrid, organic) what you want?
- Is the packed-for date current?
Once you learn to read seed packets fluently, every trip to the garden center becomes a much more strategic — and rewarding — experience.