by Leslie Cox; Monday; January 9, 2017
As much as I love the snow for its bright light in the dead of winter…I have had enough of it now. Especially since the last snowfall has stuck around for a month and there is more falling as I write this blog article. What is a gardener to do?
If you are like me and have fun growing your plants from seed, it is time to pull out the accumulated seed packets, sort through what varieties are on hand, and how many seeds are left in each packet.
It is also a really good idea to check the date stamped on the seed envelope, although not all companies include the date their seeds are packaged. It is a roll of the dice for those ones unless your memory is spot on and you can recall when you bought them.
Knowing the seed packaging date is important because each variety has a “best before date”…or speaking botanically, a “viability limit”. This means pea seeds, which are viable for 3 years…provided they have been stored in a cool, dark place (10 °C / 50 °F) with low humidity…should have a germination rate greater than 80% for three years…although it may be just a little less in the third year. After three years, the germination rate for that packet of pea seeds starts to drop off.
Industry standards will state the germination rate is only 50% on pea seeds older than three years. However, it is not unheard of for ten year old pea seeds to still have a germination rate of 40% – 50%, given proper storage conditions.
Did you know? A mature date palm seed discovered at an archeological dig in Israel was carbon dated to be an estimated 2,000 years old. It was subsequently planted and germinated successfully. That multiple centuries old seed has now grown into a productive, fruit-bearing tree.
Going back to those older seed packets…before you go to all the work of sowing those seeds, only to have big gaps between the young seedlings sprouting in the row…it is a really good idea to do a germination test. And luckily, this exercise is very easy to do. Provided you have enough seeds to do the test, that is.
- seeds (preferably 10 – 20 for representative results, but as few as 5 can suffice)
- paper towels
- ziplock bags (alternatively, you can use saucers and clean plastic bags)
- an indelible pen
- a container large enough to hold the ziplock bags in an upright position.
- Rip off one or two sheets of paper towel from the roll…depending on the size and number of seeds to be germinated.
- Write the name of the seed and the date on the upper edge of the towel. Very important, especially if you are testing more than 3 or 4 seed varieties at the same time.
- Wet the towels just enough so they are damp, but not soaking.
- If you are using saucers and plastic bags…place the damp paper towel on the saucer.
- Place the seeds on the damp paper towels, making sure they are not touching one another. In moist, semi-enclosed conditions, the seeds can develop fungal growth. Placed too close to one another, the fungus will spread given you are providing it with its favourite moist environment.
- Fold the paper towel over the seeds to cover them and slip the saucer into a plastic bag. Be sure to leave the bag open to allow air in to reduce risk of fungal growth.
- If you are not using saucers, roll up the damp paper towel with the seeds inside and place it in the ziplock bag with one end up. Do not close the bag.
- Stand the ziplock bags upright in the container.
- Place saucers or container in a warm place…on top of the fridge or the water heater.
- Start checking your seeds for signs of germinating after 2 days.
- Spritz the paper towels with water if they are starting to dry out.
Once you have determined as many seeds have sprouted as are going to…(I usually allow 10 – 14 days, but sometimes up to 21 days depending on the age of the seeds and variety)…count how many have germinated and divide that number by how many seeds you started with. Multiply the resulting number by 100 to get your germination percentage rate.
If you are a lab tech like me, you might find it helpful to make up a recording chart in Excel, or other similar spreadsheet program. I find these record sheets of seed test results to be useful for information purposes down the road.
And…if you are a true Scot and have inherited strong thrift genes from your ancestors as I have, it is not remiss to go ahead and pot up those germinated seeds from your test. However, depending on the seed variety and how many weeks are still left until the magical planting out date two weeks after your last frost, it is best to pot up sprouted seeds only if you have grow lights to place them under. Window sills will not work for seedlings waiting to be planted outside two to three months from now.