Is Cheap Seed Hurting Your Garden? Germination Rate, Vigor, and Why You Should Care

Sometimes, cheap seeds just cost too much.

I’m going to explain why in a second, but first I want you to imagine for a minute that you are pulling up to a gas station to fuel your car. There are two pumps, and each will dispense different fuels.

Pump A sells fuel that costs $7 a gallon and Pump B sells fuel that costs $3 a gallon. Which do you pick? Well, if you are like most people (price sensitive), you obviously fill up on the cheaper gas.

But now imagine you notice some fine print on Pump A: “Contains 31,000 usable energy units per gallon.” And the fine print on Pump B says: “Contains 7,000 usable energy units per gallon.” (Car-heads are laughing at me right now, but just go with it.)

So with the fine print in play the question becomes more complicated. It’s not the gallon of gas you’re paying for, not really, it’s the energy units your car needs to propel itself some distance down the road. When you do the math, Pump A is selling an energy unit for .023 cents and Pump B is selling an energy unit for .043 cents.

The cheaper fuel is actually more expensive – nearly twice as expensive, actually! Put another way, sometimes you really do get what you pay for.

Germination Rate

Okay, back to seeds. Seeds have a kind of energy unit attached to them, too. It’s the germination rate, and it can make a huge difference in what you really get out of your seeds.

The awesome, dangerous transition from seed to seedling is called germination. When a seed absorbs moisture at an appropriate temperature, a whole series of enzymatic changes convert stored starch and protein into usable energy for the seed. It’s metabolism quickens and the seed swells, putting down the first teeny roots, and eventually unfurling it’s cotyledon (seed leaves).

Here’s a quick video. It really is amazing.

In a batch of seeds with good germination, most of the seeds in the batch can successfully undergo this transition. If 89 out of 100 seeds will make it, that batch has an 89% germination rate.

Germination rate is influenced by a bunch of stuff, most of which happens long before the gardener buys the seed. Stuff like, the fertility of the field which grew the parent plant of the seed. As seed ages, it’s germination rate goes down, down, down. This is inevitable as the seed slowly, slowly, slowly uses up some of its stored energy to stay alive.

The rate at which germination potential falls is influenced by starting vigor, seed type (some seeds age-out faster than others), and care in storage. But even with the best at-home seed storage, eventually seed loses it’s punch. Luckily, it’s not hard to determine germination viability for older seeds. (More on that at the end of this article.)

Legal Minimums for Seed Germination Aren’t Good Enough

In the United States, the Federal Government regulates minimum allowable standards for seed germination. (CFR 201.31 – Germination standards for vegetable seeds in interstate commerce, if you’re interested.)

Here are the legal minimums for allowable germination rates for a few common seeds, just so you can see what’s allowed.

Federal Minimum Germination Standards

Artichoke – 60 Beans – 70 Beet – 65 Broccoli – 75 Cabbage – 75

Carrot – 55 Cauliflower – 75 Chard, Swiss – 65 Corn, sweet – 75 Cucumber 80

Eggplant – 60 Kale – 75 Lettuce – 80 Parsley – 60 Parsnip – 60

Pea – 80 Pepper – 55 Spinach – 60 Squash – 75 Tomato – 75

 

Seed sellers are required by law to test their seed’s germination regularly, and the seed must meet these minimums to be sold. When the seed house tests germination, optimum conditions for seed germination, including moisture, light and temperature are all controlled. The seed is given every possible opportunity to sprout.

All ethical seed houses want the highest possible germination rate for their seed because high-germination seed performs better for their customer, the gardener or farmer (more on this below).

Sophia Bielenberg of High Mowing Organic Seeds (a company I was proud to have as a sponsor last year), describes their process for testing seeds:

High Mowing has an in-house lab where we perform regular germination and purity tests and evaluate seedling vigor on all seed lots to ensure they pass our standards, which exceed federal germination standards. For example, the federal minimum rate for sweet pepper seeds is 55%, but High Mowing requires sweet pepper seed to pass a test with at least 75-85% germination, depending on the variety.

Our Quality Control Supervisor, Melanie Hernandez, conducts regular cycle tests on all of our seed lots every 4-6 months to ensure that the seeds meet our germination standards. High Mowing is unique among seed companies in that we have an on-site seed cleaning mill where we can perform additional cleaning to increase the purity or germination rate of a variety, by removing impurities and non-viable seeds. This ensures our customers get the cleanest, best germinating organic seed on the market with the highest degree of genetic purity.

Sophisticated seed buyers – professional farmers, mostly – know how important seed quality is, and look carefully at the results of germination tests before buying large quantities of seed. Quantities of seed over a pound must legally be labeled with the results of a germination test performed within the past 6 months, but seed packets like you and I purchase typically aren’t.

The one company I know of that regularly labels even their small seed packets with germination data is Johnny’s Selected Seeds, and it always makes me smile to see that data so transparently included. Johnny’s sells to many professional market growers, and their seed is consistently incredibly high germinating.

Seed Vigor

The quality of vigor in seeds is closely related to germination, but it’s a bit different. It’s more like seed chutzpah. Seeds with great vigor are, you know, vigorous. They’re eager to leap out of the ground, plunge their roots into the soil and throw open their leaves to the sun. The tend to sprout fast, grow sturdy, upright stems and have well colored, well formed cotyledon. All seeds that have vigor germinate well, but not all seeds that germinate have vigor.

In the real world of the garden – outside the sterile, coddled environment of a seed germination testing lab – this quality of vigor leads to seedlings that are less likely to be attacked by pests and diseases (insects and infections are drawn to the weak, just like lions nab the slowest zebra) and more likely to grow rapidly and well. A vigorous plant is more able to thrive in an imperfect environment than one without vigor, and all environments outside the lab are imperfect.

You’ll sometimes hear a term called hybrid vigor. Hybrid seeds are extremely consistent about the way they grow, and tend to be consistently vigorous right out of the gate.

Seeds with a germination percentage at the legal minimum for their type are not vigorous. They just aren’t. No professional farmer would buy seed at the legal minimum of germination. When you take them out of the lab and put them to the test where it matters – the good earth – they will often fail.

Why Vigor Is So Critical To Performance

In his book, Growing Vegetables West of the Cascades, Steve Solomon reports on how seeds of different germination rates actually perform in the field. In the field we see whether a seed has true vigor.

Solomon uses cabbage seed as an example, which has a legal minimum germination rate of 75 percent. He shows that, under excellent conditions:

• “Super Seed” with a 95% lab germination rate, can be expected to actually sprout in the field at about 65% or a bit higher.
• “Good Seed” with an 85% lab germination rate might actually germinate at 50%.
• “Legal Minimum Seed” (The 75% stuff) may only have a practical germination rate of 15%.

The field test germination numbers get worse as the conditions drop from excellent to just good, and they drop fastest for the lower germination rate seeds. Low-vigor seeds need really pampered conditions to do much of anything, and often still don’t perform.

Is this starting to sound a bit like the Gas Pump A vs. Gas Pump B analogy from the beginning of this post? Yeah. It’s not how many seeds you get per dollar, it’s how much harvest you get per dollar.

Cheap Seed Fails To Perform And You Blame Yourself

Cheap seed can be great. Genetically stable, commonly grown open pollinated varieties can be both cheap and vigorous. (Peas come to mind.) I’m not at all against saving a bit of money in the garden.

But, cheap seeds can also be a false economy. If you’re buying a packet of seeds, only 15% of which you can expect to sprout under even excellent real world conditions, that’s a huge false economy. By the time a batch of seeds declines enough to reach that “Legal Minimum” level of germination, even the seeds that do successfully grow are more likely to fall victim to pest or disease problems because they just don’t have the oomph to get the job done.

Less vigor in seeds means less chance of success in the garden. Sadly, the only folks buying seeds near the legal minimum of germination rate are likely to be backyard gardeners.

So less vigor means less chance of success for the gardener. But the distributors of those packets of no-name seed you pick up on the rack at the big box store aren’t competing on your success, i.e., how much you will eventually harvest.

They are selling, mostly, to the fairly casual or new home gardener who isn’t going to know why the seeds never grew well and is most likely going to blame themselves, or the weather, or their crappy soil, or any number of things without even considering that they may have been condemned to mediocre results right from the start with crappy “Legal Minimum” seed.

You know the most valuable thing in my garden? My time. While I can garden nearly year-round, the planting windows for many crops in the Northwest (especially the heat lovers and the fall crops) are quite narrow. If I miss those windows because my seed fails to germinate and grow, I’ve lost something far more expensive than a seed packet – I’ve lost an opportunity for homegrown food.

What You Can Do

Start With Great, High-Germination Seed

Look for seed from companies that boast in-house germination minimum higher than the Federal guidelines. This seed is more likely to be full of vim and vigor. If you email your seed house and ask what their germination standards are for a particular type of seed, they should tell you proudly. Check their numbers against the Federal minimum guidelines to get a sense of how good those numbers are. Peas, for example, should have nearly perfect germination. 80% would be terrible. On the other hand, pepper or carrot seed with a germination rate of 80% would be really quite good.

Store Your Seed Well

Cold and dry, or as near as you can get it, is what you want for the longest lasting seed. I store my seeds in the refrigerator. You can see my seed storage set up here.

Do Occational DIY Germination Tests On Older Seed

You don’t have to do this every year with every seed, but when seeds start to hit their nominal expiry date, occasionally do an at home germination test on your seed to see how much vigor it maintains before committing to the effort of planting. For more info on how long seeds “should” last, I like this chart and post from A Way To Garden.

It’s easy! To test seed germinations at home you just:

1. Count out a specific number of seeds. I usually do ten which is enough to get a rough idea of the germination rate. More seeds will give you more accurate numbers, but do you really want to “spend” 100 seeds just to see if they grow?
2. Get a paper towel just damp, not sopping wet, and fold it in half. Lay your ten (or whatever) seeds out on the paper towel, spaced out a bit.
3. Fold the paper towel over the seeds and roll up your seed test towel.
4. Slip your seed test towel into a plastic baggie to keep the moisture in, label the baggie with the date and stick your seed test someplace warm-ish. 70 degrees would be great
5. Look in any seed catalog to find the expected days to germination for the type of seed you are testing, wait that number of days, and then count how many seeds have sprouted.
6. If 8 out of 10 seeds have sprouted, you have an 80% germination rate, which is pretty good for many vegetables. If 4 out of 10 sprout, you have a 40% germination rate and the seed is, for all intents and purposes, useless.

If the time of year is appropriate for it and you really hate wasting seed, you can very carefully transfer your sproutlets to the garden or a transplant pot. Personally, I’d just feed the testers to the chickens.

Ignore Advice To Sow Weak Seed Twice As Thick

Sometime you’ll hear that, if you have a batch of old seeds germinating at 50%, you can sow them twice as thick to make up the difference. It doesn’t really work like that. By the time a batch of seed is failing a simple germination test, it’s long since failed the vigor test.

Planting twice as many weak seeds won’t make for strong seedlings, just a better chance at getting a few week plants to come up. The ones that do struggle up are then more likely to be eaten by critters or snuffed out by disease. So ignore advice to sow out really weak seed. Make it into a kitchen sink blend to play with if you want, but don’t count on it to really provide for you.

Now it’s your turn to weigh in. Do you consider germination rate and vigor when you buy seeds, or do you go on price alone?

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