Old sunflower seed - Ask Extension
I found an 11 year old sunflower seed and hope to plant it. I recall collecting it from a mammoth sunflower in 2013, but only recently had a place to ...
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Old sunflower seed #862002
Asked March 19, 2024, 11:49 PM EDT
I found an 11 year old sunflower seed and hope to plant it. I recall collecting it from a mammoth sunflower in 2013, but only recently had a place to plant it. Does it have a chance, judging by the pictures? If so, what should I do to give it a chance? How much space does it need?
Linn County Oregon
Expert Response
Dear Stephanie,
This is awesome. Seeds do last a very long time.
You can do the wet paper towel germination to see if the seed will germinate. Take a wet paper towel, put the seed in it, fold it over so all sides are wet and place in a plastic bag, sealed to keep the moisture in. Does not have to be dripping wet, just really moist. Place in a warm place so the heat will permeate the bag.
You should see some germination in several days. Using a clear bag and one fold over for the paper towel, you will have some idea if the seed is germinating.
If it does, have a small pot (4 inches is good) with moist potting soil in it and gently open the bag and towel and place the germinated seed in a small hole without damaging the root. Cover with enough soil to hide the seed. Soil should be moist like a rung out sponge.
Place in a sunny window or on a heat mat, temperature around 70 degrees for several days. This is not the time to put the seed in the ground though, too cold and more rain is coming.
Once the seed is up, it will need a good light source indoors, keeping the soil warm. You can take it off the heat mat and again, place in a sunny window. Turn the pot daily so the plant does not strain to get to the light. A grow light is best.
Now is not the time to do any of this. If the seed is viable and germinates, it will grow quickly and Mammoth sunflowers need a lot of room along with warm soil and plenty of sun as you know having grown them in the past. Waiting to the end of April when the temperatures should start to warm up is best.
Before transplanting the plant, check your soil temperature. You can use a soil thermometer or a meat thermometer. Soil temperatures above 55-60 degrees are best.
If you are successful and the temperatures start to warm up, harden off the plant by putting it out in the sun out of the wind for an hour, next day 2 hours, third day longer and so on until the temperatures at night are over 55 degrees.
Good luck Stephanie. If you have any further questions, please contact us again.
This is awesome. Seeds do last a very long time.
You can do the wet paper towel germination to see if the seed will germinate. Take a wet paper towel, put the seed in it, fold it over so all sides are wet and place in a plastic bag, sealed to keep the moisture in. Does not have to be dripping wet, just really moist. Place in a warm place so the heat will permeate the bag.
You should see some germination in several days. Using a clear bag and one fold over for the paper towel, you will have some idea if the seed is germinating.
If it does, have a small pot (4 inches is good) with moist potting soil in it and gently open the bag and towel and place the germinated seed in a small hole without damaging the root. Cover with enough soil to hide the seed. Soil should be moist like a rung out sponge.
Place in a sunny window or on a heat mat, temperature around 70 degrees for several days. This is not the time to put the seed in the ground though, too cold and more rain is coming.
Once the seed is up, it will need a good light source indoors, keeping the soil warm. You can take it off the heat mat and again, place in a sunny window. Turn the pot daily so the plant does not strain to get to the light. A grow light is best.
Now is not the time to do any of this. If the seed is viable and germinates, it will grow quickly and Mammoth sunflowers need a lot of room along with warm soil and plenty of sun as you know having grown them in the past. Waiting to the end of April when the temperatures should start to warm up is best.
Before transplanting the plant, check your soil temperature. You can use a soil thermometer or a meat thermometer. Soil temperatures above 55-60 degrees are best.
If you are successful and the temperatures start to warm up, harden off the plant by putting it out in the sun out of the wind for an hour, next day 2 hours, third day longer and so on until the temperatures at night are over 55 degrees.
Good luck Stephanie. If you have any further questions, please contact us again.
