The Cheat Sheet in Your Hand: How to Actually Read a Seed Packet...And Stop Guessing

[Mike]

I'll admit it, I'm a sucker for a good looking seed packet. You're standing there in the garden center at Walmart or Home Depot and you spot that perfect looking, giant red tomato or bright yellow squash and it just grabs you. I'm building my garden to build food, though, not just look at someone else's perfectly grown photos, and rarely my own fruits and vegetables look like the ones in the picture.

They can though! While I realize those perfect photos on the front of the package are just a sales pitch, the back of the packet is the manual that determines of you feast or fail. Does your garden harvest look like the front of the packet or does it just whither away?

It took me a bit, when I first started gardening, to figure out what all those numbers and maps actually meant, so I wanted to break it down here in case there are other folks struggling to read the back of their seed packets. Here is how I decode the seed packets now that I know better:

Days to Maturity (The Most Confusing Number)​

This is the big one. You'll see a number like "75 Days" printed boldly on the back. Here's the trick, though...it doesn't always mean 75 days from the moment you drop that seed into the dirt.

• For things you transplant, like tomatoes and peppers, that clock usually starts when you put the plant into the ground, and not when you plant the seed indoors.
• For direct-sow seeds, like your beans and radishes, the clock does start the day you plant the seed.

This is a huge deal for us here in North Texas because if I buy a tomato that says "90 Days" and I don't get it into the ground until April, there's a good chance the July heat is going to roast those tomato plants before I ever get a slice onto my burger. I look for lower numbers so I can try to beat the heat.

The Planting Calendar (Take this with a Grain of Salt)​

Most packets have that little color-coded map of the US, or a chart saying "Sow in April-May". Honestly, I mostly ignore this. Those maps are super generic. "Spring" in Minnesota is very different from "Spring" here. If I planted my spinach when the packet says it's time to plant spinach, it would already be too hot. I usually stick to local planting calendars, asking other gardeners, or you can even ask the folks at the extension office, and just use the packet for help with technique, not the timing.

Hybrid (F1) vs Heirloom vs Open Pollinated​

I used to think this was just marketing fluff, but actually matters for what I'm trying to build.

• Heirlooms/Open Pollinated: These are the classics. If you save the seeds from these peppers, you can plant them next year and you'll get the same pepper. I always try to buy these if I have a choice.
• Hybrids (F1): These are crosses between two parents to get specific traits, like disease resistance. They're great plants, but don't bother saving the seeds. They won't grow back "true" next year.

If you really want to get serious about gardening, I'd recommend doing a mix of the two so you can see what you like best for yourself. Hybrids are nice because they're a bit "tougher", but heirlooms are going to have a much better flavor, and that's what I'm after. Maybe sometime in the future I'll try to experiment with nutritional value from both, but I'd expect the heirlooms to win that battle too.

"Determinate" vs "Indeterminate"​

If you're buying tomatoes or beans, you have to look for these words.

• Determinate: The plants grow to a certain size, drop all their fruit at once, then stop. These are good for canning, or if you want to just be done with harvesting quickly.
• Indeterminate: This is the "vine" type that keeps growing and growing until the frost (or, here in North Texas, the heat) kills it. Here's a tip: don't try to grow and indeterminate tomato in a small tomato cage on your porch or patio. These dudes will eat up all that space in a hurry.

The "Packed For" Date​

Check the year stamped on the bottom! Seeds are alive, and they don't live forever! If I'm buying new, I want to make darn sure they say "Packed for 2026 (or current year)". If I'm digging through my seed stash, I know things like onions and corn won't last a long time (1-2 years), but tomatoes and peppers can last many years as long as they're properly stored.

The Bottom Line​

The packet seed is basically a little encyclopedia. I used to just tear them open and toss them into the trash. These days I keep them stored safely in a special "seed drawer" so I can easily remember what I planted.

What about y'all? How many of y'all mostly ignored all that info on the seed packet and just planted whatever you saw that looked good?