15 Seeds You Should Never Soak Before Planting
Soaking seeds before planting can help kickstart germination and boost growth. But that doesn't apply to all seeds. Gardening expert Madison Moulton lists 15 seeds you should never soak before planting.
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To soak or not to soak—that is the question. At least, that’s the question we’re tackling today. You’ll find plenty of wisdom online (including here) on which seeds you should soak before planting if you want to boost germination. But there isn’t much on which seeds you should never soak.
This usually comes down to size and how seeds react to water. Put simply, the smaller the seed, the harder it will be to sow evenly if soaked beforehand. Some seeds are also mucilaginous, developing a slimy coating in water that makes them almost impossible to handle.
Don’t overcomplicate the process if you’re dealing with any of these 15 crops. They will grow just fine without soaking beforehand, and in most cases, soaking will actually decrease your chances of germination.
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Lettuce
Lettuce seeds are not the smallest out there, but they are pretty tiny. Immersing them in water can leave them soggy and difficult to handle, potentially leading to uneven germination and weird spacing. They also need light to germinate, so you’ll see far better results if you sprinkle them when they’re dry.
For best results, sprinkle lettuce seeds directly onto your seed-starting mix (or garden bed if you’re direct sowing), and just lightly press them into the soil. They need only minor contact with the soil for moisture, giving them as much light for proper germination as possible.
Radish
Radish seeds are slightly larger than lettuce but still pretty small. But their size is not the only consideration. They form a slimy coating after soaking, causing them to clump together and become difficult to handle. You’ll have a far easier time sowing without soaking, although some gardeners still do.
Sow radishes in loose, well-draining soil about half an inch deep. Then, simply keep the soil consistently moist (but not soggy) to encourage rapid germination without a pre-soak.
Celery
Celery seeds look quite tough, and some gardeners choose to soak them before planting. But it’s really not necessary, and soaking can cause them to clump together, compromising both even distribution and germination. They grow well when undisturbed.
Celery does not need to be planted deeply. After sowing onto well-draining soil, press them lightly into the surface without fully covering them. A light dusting of soil is enough to maintain moisture levels and encourage germination.
Carrot
From the same plant family, carrot seeds can be treated in the same way as celery. Soaking them can result in clumping, making them far harder to sow than if you skipped the step altogether. Why go through the extra effort if you don’t have to?
Direct sow carrots in a slightly sandy and well-draining soil. As root crops, they don’t transplant well, so it’s best to plant them straight into the soil outdoors. Check your local last frost date and sow a couple of weeks before.
Spinach
Spinach seeds are also on the small to medium side and germinate pretty quickly, leaving them on the side of seeds you should never soak. They germinate perfectly well without soaking beforehand. If you do choose to soak them, you’ll find them difficult to place correctly.
While it is certainly not a root crop, spinach also doesn’t appreciate being moved after planting. Sow spinach directly into the garden, covering them with about half an inch of soil—just enough to hide them from birds.
Chia
Chia seeds have a gelatinous coating that activates when they get wet, one of the most widely known seeds you should never soak. You’ll know what I’m talking about if you make smoothies with chia often. After soaking, chia seeds become a gloopy mass that makes even sowing almost impossible.
For the best results, simply sprinkle chia seeds onto the surface of a fine, well-draining seed mix. Don’t bury them too deep. Place the tray in a spot that receives plenty of sunlight, or under grow lights.
Strawberry
Looking at a strawberry up close, it’s easy to see why you should never soak them before planting. Strawberry seeds are incredibly small and delicate. Any pre-soaking may cause them to stick together, leading to uneven distribution. Since they take a while to germinate, you’ll only notice the issue after a couple of weeks.
Sow strawberries by lightly scattering them over a seed-starting mix. Allow for a natural period of stratification by sowing them at the right time for your climate (around 3 to 4 months before your last frost).
Oregano
Moving on to herbs, oregano is another crop that some gardeners do choose to soak, but that isn’t really necessary. They handle germination well without intervention. Soaking them for too long might actually hinder the germination process, so it’s far better to avoid the risk and skip it completely.
The best method for oregano is to start the seeds indoors about 6 to 8 weeks before your last frost date or sow them directly in your garden if you’re in a warmer climate. Lightly press the seeds into a well-draining soil mix, leaving them just barely covered.
Marjoram
Marjoram seeds are similarly far easier to sow if you never soak them. Part of this is size, as these seeds are tiny. So small, in fact, that sowing in trays is recommended rather than sowing outdoors. Soaking for too long will cause the seeds to become soggy and clump together, undermining even and quick germination.
To plant marjoram, the process is the same as planting oregano. Don’t cover the small seeds with too much soil, or they will struggle to germinate and make it to the surface.
Thyme
Thyme seeds suffer from the same problem as marjoram: they’re super tiny. You’ll have a far easier time sowing as they come than trying to soak them beforehand. These seeds are best left dry and germinate well as long as the soil they’re planted in remains lightly moist to encourage germination.
Sow thyme on the surface of a well-draining mix as evenly as you can, considering their size. There’s no need to bury them. Just keep up with gentle watering (to avoid dislodging the small seeds) and you shouldn’t have any issues with germination.
Basil
Basil seeds also benefit from staying dry until planted. If you try to soak basil, you’ll see a slimy coating develop around the seeds to help them anchor into the soil. However, this slime will make it far more difficult to get them out of a water soak.
Indoor sowing in trays is recommended for these herbs. Start them indoors 4 to 6 weeks before transplanting outside. Scatter them over a well-draining soil mix and cover them with only a quarter inch of soil to promote germination.
Petunia
Petunia seeds are incredibly tiny and delicate—so small you can hardly see them. But there’s no doubt they pack the potential for masses of blooms. Because of their minuscule size, pre-soaking makes sowing even harder than it would be if you sprinkled them over the soil dry.
Instead of soaking, simply scatter petunia seeds on top of a seed-starting mix. They need light to trigger germination, so press them gently into the surface without covering them completely. Place the tray under grow lights or on a sunny windowsill and maintain consistent moisture.
Pansies
Pansy seeds are also small and subtle. If you’ve ever tried collecting them, you’ll know how tough they are to handle as it is. A pre-soak is not only unnecessary but could be counterproductive, placing them firmly in the category of seeds you should never soak.
Direct sowing is recommended for these cool-season flowers. Start sowing 4 to 6 weeks before your average last frost date, or midsummer for fall and the following spring bloom. In mild climates, sow in late summer for cool-season blooms.
Snapdragon
You should never soak Snapdragon seeds before planting due to their size. They are super small and easier to sprinkle over the soil when they’re dry. Soaking will cause them to clump together and stick to your fingers when you’re trying to plant.
Indoor sowing in trays is recommended, starting around 8 to 10 weeks before your last frost date. Gardeners in mild climates can also direct sow in late summer to early fall for winter and spring bloom. They perform best when sown shallowly in cool climates.
Foxglove
The final entry on this list is foxglove, and I’ve left it till last for good reason. Foxglove seeds look more like dust than seeds, and you’ll be forgiven for mistaking them for a pile of fine dirt or sawdust. Soak them, and planting evenly becomes almost impossible.
Foxgloves don’t transplant well, so it’s better to wait until the right time to direct sow outdoors or sow indoors in biodegradable pots if you want to get a head start on the season. Sow 1 to 2 weeks after your average last frost date, until 2 months before your first fall frost date for blooms the following spring.
