How to Germination Test Your Seeds

IMG_0685-2Looking through the seed packs of seasons past, it’s not always easy to know which seeds will reliably germinate. And which seeds to buy for the coming season. Here are some tips on how to test your seeds so you know which will be most productive and abundant for you.

Count out an exact number of seeds. We usually count at least 100, making the math easy: if 89 sprout and 11 don’t, you have 89% percent germination. Make sure you test at least 10 seeds, but the more seeds you test the more accurate your results will be.

Wrap your freshly-counted seeds in a moist paper towel, tuck them in a plastic bag and seal the bag. Label the bag with variety, seed count and date the test began. Keep the bag in a consistently warm place in your house (60-70 degrees F).

After a week, open up the bag and count the seedlings. Some seeds take longer to germinate than others; some seeds require unusual conditions to germinate, as well. But most garden seeds will sprout with this simple test within a week. And by the second week you’ll certainly have a sense of whether or not they’ll be reliable once the snows melt.


A couple of the common pitfalls


Relatively consistent 60-70 degree temperatures will suit many seeds. If seed is too cool (below 55 degrees F), it may not germinate. There are exceptions: claytonia germinates even in the refrigerator!

If seed is too warm (above 80 degrees F) germination also decreases. Brassicas and spinach are especially hesitant to germinate in warm conditions. Some crops, like lettuce and kale, germinate best when they chill in a refrigerator for three days prior to becoming moist. Other varieties (like our Habanada pepper) germinate best in temperatures that fluctuate 15 degrees F with a day/night cycle.


If seed is too wet, or especially too dry, they will not germinate well. Fortunately, moisture issues are generally easier to diagnose than temperature issues. A spray bottle is handy to moisten any paper towels that are too dry. Some common crops have moisture preferences you might not expect! Cucumbers, for example, prefer to germinate on the dry side.

And one more idea if you’re struggling

Potassium Nitrate (KNO3)

Some seeds prefer to grow in soil rather than a moist paper towel, period. For these we spray with a dilute solution of KNO3 (also called saltpeter) to simulate the chemistry they experience in soil that inspires them to germinate. For some seeds, this softens the seed coat in a way water would not; for others it breaks their dormancy. Tomato, parsley, chard and pepper are all crops we germination test with KNO3. Important note: it is possible to get a good germination test off these crops without KNO3. But if you are struggling, you now have an idea of how to troubleshoot.

Categories: Home Garden, Seeds, Tips | 4 Comments

Home Ground with Roger B. Swain

Roger B. Swain


The steam rising off the pans of boiling maple sap, the receding snow banks out the sugar house door, the pair of newly-returned turkey vultures soaring overhead – these are all signs that spring, however delayed, is finally upon us. The spring peepers will soon be calling from the marsh at night, a chorus of optimism if there ever was one, and it seems a good time to introduce a new project, a series of seasonal reports and opinions on vegetable growing. This has come about through a chance encounter with Matthew at the Connecticut Flower & Garden Show where I was lecturing this winter. I stopped to admire his gallon jar filled with kernels of ‘Magenta Parching’ corn and one thing has led to another.

By way of introduction let me say that I have been raising vegetables on this southern New Hampshire hillside since I was a teenager, half a century ago. This has been purely non-commercially, although it has served me well as a practicum for my years as Science Editor of Horticulture magazine and as host of PBS-TV’ s The Victory Garden.

In my semi-retirement I have the luxury of reflecting on the whys as well as the hows of what we grow and eat. The booming enthusiasm for whole food and food that has been locally grown is both welcome and laudable, but it should not eclipse the homegrown. Just as recycling a grocery bag is trumped by reusing one, and in turn by not needing one at all, so the case can be made for the superiority of raising at least a portion of one’s food. It is not just the calories consumed or the dollars saved that matter. There is also the connection that is established to those who labor elsewhere to feed us.

Signs of spring

Signs of spring

To grow even a few vegetables at home is a lesson in ecology, and a reminder that the domestication of plants for our benefit requires that we, in turn, provide our plants with a level of care , from fertilizer to pest control, that their wild progenitors do not need. Finally there is the well-being that comes from a sense of self-reliance, and a generous measure of good health from the exercise. All these things we hope to expand upon in the months to come.

I am joined in this endeavor by Birgitta Keinanen, a source of inspiration and ideas, who, though younger than me, spent a dozen years gardening at Rosaly’s Garden, the oldest and one of the largest organic producer of vegetables in this state. As the first buds swell and we ready seeds to go into the soil again, wish us well, as we do you.

Roger B. Swain

Categories: Home Garden, Home Ground, Seeds, Tips | 1 Comment

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