- Petunia seeds can be stored for up to three years without significantly losing their viability, however they are most effective when planted within a year of collection.
- In the spring, dampen three layers of paper towels, scatter 10 petunia seeds between the layers, and then fold the towels in half. For a week, store the towels in a plastic bag. To determine the germination viability rate of the seeds, count the number of sprouted seeds at the conclusion of the one-week period. For instance, if seven out of ten seeds germinate, the germination viability of the seeds is 70%.
In addition to having a Master Gardeners certificate in Oregon, Shelley has been writing and editing garden stories for ten years.
How old can seeds be and they will still sprout?
Now, the new seed you ordered for this year will be ready to plant and germinate. You might not be aware, but many types of flowers and vegetables have government criteria for seed germination. Pinetree will only pack a seed if it exceeds the legal minimum.
But what about that huge basket of seeds you still have from the previous season? Those seeds probably still have a lot of developing to do, but I advise verifying their viability beforehand to avoid any future germination heartbreak. In a word, seeds are living organisms that arrive to us inert. Many seeds can stay dormant for years after their indicated use-by date when kept in correct storage conditions.
However, there are a few elements that affect the vitality of your seeds:
- Age Every seed has a shelf life of at least a year, and many of them are at least two years. After that, the rate of seed germination may begin to decline. This is not to mean that these seeds can’t germinate and grow into strong plants. They will. Given that some seeds won’t germinate, you might need to plant more than you initially thought. See the simple method for determining whether your seed is viable below.
- type/varieties of seeds
- Some plant kinds have shorter seed lives by nature, therefore it’s recommended to use them within a year. Asters, delphinium, leeks, onions, parsley, parsnip, and phlox are other short-lived seed examples. While some plants, such as basil, beets, Brussels sprouts, cabbage, chard, cucumbers, kale, lettuce, pumpkin, radish, squash, tomatoes, and zinnias, have a fairly lengthy shelf life. You can find that various types of the same crop have varied germination rates. Since the pelleting procedure can shorten the seed’s shelf life, it is advisable to use pelleted seed within a year.
- Storage
- Now that’s important! The first step to ensuring your best germination success for the following growing season is carefully saving your seed. Unused seeds ought to be kept in a cool, dry place (ideal temperature of 50oF at 50 percent humidity). The viability of the seed can be significantly reduced by exposure to heat, sunlight, or dampness. For indoor gardeners, the best option for storing seeds is to seal them in a glass container (which must be moisture-proof) and keep them in the freezer or refrigerator. In order to assist wick away any potential moisture, you can even place some rice in the bottom of the seed jars. The anticipated lifespan of properly stored seed can be many, many years longer. Just a reminder: after removing your seed jars from the fridge, let them warm up to room temperature before opening. This prevents condensation from possibly forming.
And proper seed packet storage extends beyond long-term preservation to daily use when you’re spreading seeds outdoors. I admit to having left one or two seed packets outside in the greenhouse (or sometimes, even right out on a garden bed). What I discovered the hard way was that by doing that, I exposed the seeds to high temperatures, sunlight, and humidity, which decreased their likelihood of germination.
While age, variety, and storage are the key three considerations, there are a few more elements that can affect a seed’s ability to germinate, including:
- Light While some seeds require darkness to germinate, others require light.
- Scarification and pre-soaking
- Some seeds have hard seed coverings on the outside, which might be difficult for the seedling to penetrate. Presoaking the seed overnight will soften that outer shell. In order to scarify the seed coat and essentially provide a hole for the seedling to emerge through, you can either use sandpaper or a knife.
- Cold Therapy
- Some seeds can’t germinate until they’ve been exposed to a period of cold. The plant will determine how cold and for how long, but for the most part, it may simply be put in the refrigerator for a few weeks before seeding.
Your seeds, especially if stored properly, may most probably have a little more oomph than this list suggests.
To test the viability of your seed, do a germination test:
- An absorbent paper towel is folded in half.
- Take 10 seeds and scatter them on the wet towel.
- The seeds should be covered with a towel and stored in a warm place in a zip-top bag.
- Open the bag and check to see what has sprouted after 3–5 days. Depending on the type of seed and the climate, some varieties may take up to 10 days, but this will give you a decent idea of how your seeds are doing.
Simply put those seeds out in the garden at a heavier pace, keeping in mind that not all may germinate, if the germination rate is lower but there is still viability.
The approximate lifespans of vegetable, herb, and flower seeds, when stored appropriately, are listed below. This is merely a projection. While some seeds have lasted a little bit shorter, many have survived for far longer. When utilizing older seed, it’s recommended practice to perform a fast viability test to determine your germination rate before planting.
How long are seeds good for?
The average vegetable seed has a shelf life of two to three years, although some, like those for onions, lose their quality sooner. However, lettuce can still effectively sprout five years later. To store seeds effectively, make sure they are completely dry, put them in an airtight container, and maintain a constant cool temperature.
The table below, which was assembled from local sources, shows the typical years of viability for properly stored vegetable seeds. There will be some variation due to the different types of seeds and whether or not the seed was fully mature and stored dry.
Should petunia seeds be soaked?
One of the most well-liked flowering annuals for many years has been petunias. Their appeal is explained by a number of appealing qualities. Petunias are simple to grow, reliably bloom throughout the summer, and come in a variety of colors, flower styles, and growth behaviors.
In the spring, most gardeners purchase petunias from their neighborhood garden center or greenhouse. Petunias can, however, also be started inside in the late winter. Ten weeks or so before the day you plan to plant the petunias outdoors, start the seeds indoors. (Petunias ought to be planted outside once the risk of frost has passed.) In Iowa, late February or early March is a good time to plant.
A suitable germination media is one that has been commercially produced, like Jiffy Mix. Seed-starting containers must to be spotless and have drainage holes on the bottom. Prior to disinfection, previously used containers should be cleaned in soapy water and dipped into a solution of one part chlorine bleach to nine parts water.
Up to 1 inch from the top, fill the container, then lightly press down. The medium should then be moistened by soaking the container in water slightly. Remove the container once the surface is moist, let it drain for 15 to 20 minutes, and then plant the seeds. Another method of moistening the medium is via a sprinkler’s tiny spray.
Petunia seeds are quite tiny. Each ounce contains between 250,000 and 300,000 seeds. It can be challenging for many backyard gardeners to plant the excellent petunia seeds. Thankfully, pelleted petunia seeds are frequently accessible. Pelleted seeds are seeds that have been coated with a substance to make them bigger and more manageable. Sow the seeds carefully on the soil’s surface, and then use a pencil or small piece of wood to gently press them into the germination media. Don’t bury petunia seeds in the germination mixture or cover them with other material because they need light to gerinate. Use a spray or partially submerge the container in water to completely damp the medium after sowing.
For the best seed germination, uniform medium temperatures and moisture are necessary. Place the container in an area that is warm (75 to 80 degrees F) and well-lit. Place a clear plastic food wrap or plastic dome over the container to ensure constant moisture levels. Avoid placing the covered container in the sun. Inhibiting or preventing germination may be due to the high temperatures that may arise from direct sunshine. In 7 to 10 days, petunia seeds should start to sprout.
As soon as germination takes place, remove the plastic food wrap or dome. After that, put the seedlings in a sunny window or beneath fluorescent lamps. Fluorescent lights should be turned on for 12 to 16 hours and placed no higher than 4 to 6 inches above the plants. It should be between 60 and 65 degrees Fahrenheit. When the seedlings have three genuine leaves, transplant them into plastic cell packs, peat pots, or other containers. Continue to grow the plants in a cool area under fluorescent lights or in a bright window if you want stocky plants. Between waterings, let the potting mix dry. Fertilization should not be required if a commercial potting mix with a slow-release fertilizer is used. For potting mixes without a slow-release fertilizer, one application of a diluted fertilizer solution every two weeks ought to be plenty. Before planting the seedlings into the garden, let them harden off outdoors for a few days.
Petunias: Do they self-seed?
Petunias are a member of the Solanaceae family, which also contains well-known plants like Nicotiana, tomatoes, and peppers. Petunias are fragile annuals that require a lot of sunlight and sufficient moisture to thrive. In the ideal environment, they bloom all summer long and well into the fall. If left to their own ways, they might reproduce via seed, but the flowers won’t have the same hue as the parent plants’.
How can I prepare petunias for the following season?
The first option is to place the plant in a dormant state somewhere that is sheltered from frost, such a garage. The second option is to care for the petunia like a houseplant and maintain it in a bright area of the house.
Remember that the majority of petunias are perennials with a limited lifespan; they typically bloom for just three to five years.
As Dormant Plants
The simplest method for keeping petunias alive is this. While some plants, like fuchsias and geraniums, do well when grown indoors as houseplants, cultivating petunias that way can be a bit of a challenge.
This is due in part to the fact that you are forcing these plants to thrive indoors under artificial conditions because they normally go dormant when the days get shorter.
Trim your petunia back once you become aware that a freeze is imminent or when the temperature starts to consistently fall below 40 degrees Fahrenheit. You should remove all of the plant’s blossoms and trim the stalks back by at least a third.
You should dig up your petunia and knock or wash away all of the soil from around the roots if it isn’t currently growing in a container.
Look closely at the plant for any indications of illness or pests. Since many pests hide or flee the plant when it is disturbed, you might not see them there, so keep an eye out for droppings, eggs, or webbing.
In your home, where they could infect any more plants you have there, you do not want to introduce these pests or disease pathogens.
Put the transplant into a container big enough to hold the root ball. It should have sufficient drainage and be filled with brand-new potting soil.
Put it in the brightest area of the house you have access to. Ideally, the plant should be put in full sunlight, but if necessary, you can add some grow lights to help supplement the available natural light.
Reduce the quantity of light the plant is receiving gradually to try to match the length of daylight that the plant is now experiencing outside.
You first want to water as usual as well. Every week, lessen the amount until the soil feels dry for an additional half-inch before watering.
In other words, the soil should feel constantly moist throughout the first week. The top half-inch should be given a week to dry out. Before you water again the next week, the top inch of soil should feel dry.
Within a month or two, the plant will lose all of its leaves. Although it may not look appealing, the plant is still alive; it has simply entered a dormant state and is directing its energy toward the roots rather than foliage or blooms.
Stop watering at that point, get rid of any leftover leaves that have fallen, and relocate the pot to a dim area, such your garage or basement.
Your petunia shouldn’t freeze, but it shouldn’t be too cold either. A temperature of between 40 and 50 degrees Fahrenheit is optimal.
It’s time to give your plant a rest right now. During dormancy, no additional watering or special attention is needed; simply make sure your plants have the right temperature and low light levels in their temporary home.
About six weeks before to the latest anticipated frost date in your area, reverse the procedure by gradually adding more water and relocating the pot to a more sunny area of the house.
You want to expose the plant to gradually increasing levels of daylight each day, just as you gradually decreased the light to keep up with the declining daylight outdoors.
Consequently, place it in a location where it will get a few hours of indirect light and a couple of hours of direct sunshine (or supplemental light). Increase this gradually over a few weeks until it can sit in the sunlight.
The petunia should be hardened off for a week before being placed back outside full-time once the last average frost date of the season has passed, provided that there is no chance of freezing weather.
For the plant to harden off, you must leave it outside in a protected area with indirect sunlight for an hour before bringing it inside again. Give it an extra hour outside the next day.
Add an hour on the third day, another on the next, and so forth, until it can withstand a full day in the sun and is prepared to go back outside.
You may now care for your plant in the same ways you would any petunia in terms of water, fertilizer, and sunlight.
It can either be planted in the ground or replanted in a bigger container. We were able to place the plant in a small container while it was dormant, but now that it is actively growing, it will require more space.
With the help of our growing petunias guide, you can ensure that your plant is completely happy in the garden.
As Houseplants
The benefit of using this method is that you can continue to enjoy your petunias all year long. The difficulty, though, is that your plant will wish to become dormant. For active growth, petunias require a lot of sunlight.
As stated in the section above, bring your plant indoors, but don’t prune it. Dead leaves and blooms should only be removed.
Place the pot in a place that gets enough of sunlight, and add a grow light to help during the shorter winter days.
If you don’t get at least 10 hours of light each day naturally in the winter, you’ll need to use the grow lamp for a portion of the day to keep your petunia from falling dormant.
Use an all-purpose fertilizer made for plants growing in containers every six weeks to fertilize your plants.
This should ensure that your petunia continues to develop over the winter (though most likely without blossoms), but if it does manage to drop its leaves, proceed as if it had gone dormant as stated above.