How To Grow Alyssum From Seed 

Growing plants from seeds isn’t always easy, and some seeds can be difficult to germinate. If you like the pink, purple, or white flowers of beautiful alyssum plants, you might wonder if you can plant them from seed in your garden. 

You can grow alyssum from seed by planting it directly into the ground. The seeds are easy to grow because they don’t need to be prepared for planting, such as by being soaked beforehand to soften their coating. 

In this article, I’ll explore ways to grow alyssum from seed so you can add these beautiful flowering plants to your garden. By following the tips in this article, you’ll successfully grow alyssum from seed. Let’s get started! 

1. Prepare the Alyssum Seeds Before Planting

Some seeds require soaking before they’re planted. This ensures that the water can gently soften the hard seed coating and ensure an easier germination process. However, this isn’t required for alyssum seeds because they are too small. 

That said, you should still prepare the alyssum seeds to increase their chance of germination. 

You can do this by keeping the seeds moist and following these steps:

  1. Moisten a paper towel without making it too soggy. 
  2. Place your alyssum seeds on it. 
  3. Keep the paper towel in an airtight plastic bag. 
  4. Check the seeds daily for progress. 
  5. When the seeds start to sprout, they’re ready to be planted in the ground (or in a soil medium if you’re planting them indoors).  

2. Stratify Your Seeds 

Another important step to follow when preparing your alyssum seeds for planting is stratifying them. 

Even though alyssum seeds can easily grow from seed, stratification increases the odds. This process involves storing the seeds in cool temperatures to break their dormancy and help them get accustomed to cold weather conditions.

Stratifying alyssum seeds is easy to do, and you can simply store them in your fridge. After putting them in a moist paper towel in a sealable bag, place the bag in the fridge. 

If you’ve already sown the alyssum seeds in a soil medium on a tray, you should store the tray in your fridge for a few weeks. 

Both of these methods will ensure that your alyssum seeds are properly stratified before planting. 

3. Plant at the Right Time 

It’s essential to stay informed about when the last frost is expected in your area, as the perfect time to plant alyssum seeds is after a frost. 

Keep the seeds indoors for a few weeks before transplanting their seedlings into the garden. Make sure that you wait for the seedlings to grow to at least 1.6 inches (4 cm) before transplanting them. 

If you want to plant the seeds directly into the ground, you should plant them during the spring when the frost is over in your region. Planting your alyssum seeds when the weather is warm encourages the alyssum plant to produce flowers earlier, which is a bonus if you want to add more color to your garden. 

4. Spread the Seeds With a Salt Shaker 

Using a salt shaker is an easy way to sprinkle seeds onto your soil. If you are planting alyssum seeds into a planter or a small pot, you’ll need to shake the shaker twice or three times so that enough seeds come out. 

Another method that will make it easier to spread seeds across the soil is to use a folder to pour them. Press the folder lightly so the seeds will gather in the crease, forming a line of seeds that will be easy to direct into the soil and where you want to plant them. 

5. Give the Seeds Enough Light 

Your seeds require enough light so that they will sprout and grow. Alyssum seeds need to be planted in full-sun or partial-shade conditions, but their seeds require lots of light, or they won’t be able to germinate.

When alyssum seeds don’t receive enough light to encourage them to grow, they can become thin and scraggly. This is especially the case when you’re growing alyssum in pots.  

By ensuring that your alyssum seeds have enough light, they will germinate within five to 14 days

Once your seeds germinate, and seedlings appear, you must ensure that the plants have at least six hours of sunlight per day. 

6. Plant The Seeds in Well-Draining Soil 

Your soil needs to be moist until the alyssum seeds germinate, which will take about one to three weeks. However, do not give your seeds too much moisture, as they should not be in soggy soil

This is an important tip to remember with any kind of seed you’re growing. If the soil is too moist, the seeds will rot before they get the chance to sprout. 

You can test if your soil is too wet by taking a clump of it with your hand and squeezing it. If it holds its shape when squeezed into a ball and also maintains its shape when you tap it with a finger, the soil is too wet. 

To remedy this issue, you should check how well your soil drains before planting your alyssum seeds. 

You can do this easily by following these steps: 

  1. Dig a 12-inch (30 cm) deep hole in the ground, and make it about 12 inches wide. 
  2. Fill the hole with water. 
  3. Allow the water to drain. 
  4. Refill the hole with water 12 hours later. 
  5. Check how long it takes for the water to drain. 

The soil has good drainage if the water drains within two or three hours. If it takes less or more time to drain, both indicate soil that doesn’t have a decent level of drainage.

If you’re dealing with drainage problems or your soil is too wet to work with, you should add garden compost with a fork. This will enhance its drainage while also nourishing the soil. 

7. Avoid Sandy Loamy Soil 

Although alyssum seeds grow quickly, this shouldn’t cause you to assume that you can grow them in any kind of soil. 

While you want to avoid sowing seeds in wet soil, you also need to avoid giving them sandy loam soil – they prefer loamy soil. This is because this kind of soil dries out very quickly, which is problematic for alyssum. After all, it’s a shallow-rooted plant. 

If you’re dealing with loamy soil in your garden, you can change it with organic matter.

To encourage better moisture retention, you can use various organic materials, including: 

  • Composted chicken or cow manure
  • Grass clippings 
  • Dried leaves 
  • Peat moss

Test the soil to confirm that it is, indeed, loamy. You can do this by taking a handful of soil and pressing it with your finger. 

If it crumbles easily, you’re dealing with loamy soil. If, on the other hand, the soil becomes gritty and forms a ribbon as you squeeze it between your finger and thumb, you have sandy loam soil. It will also break apart before reaching a length of 1 inch (2.54 cm). 

8. Use a Seed-Starting Compost 

There are some essential tips to follow if you want to plant alyssum seeds indoors. One of them is to fill your pots or containers with seed-starting compost that encourages plants to grow while preventing the soil from becoming too soggy. 

After you’ve added the seed-starting compost mix, you should follow these tips to ensure you plant your alyssum seeds properly indoors:

  1. Sow a few alyssum seeds into the compost. 
  2. Gently press the seeds into the surface, but don’t cover them too much.
  3. Add a layer of perlite. This is a material that maintains soil moisture while allowing the natural light to reach the seeds, as the University of Georgia Extension reports.

9. Get the Right Soil pH 

Another important factor to consider when planting alyssum seeds in your garden is the soil’s pH. Although alyssum adapts to different soil types, you should keep the soil’s pH level between 6.0 and 7.0, which is slightly acidic to neutral soil. 

You can test your soil pH by using a meter. If you’re dealing with alkaline soil, you can make it more acidic to accommodate the needs of your alyssum plants by adding organic materials.

These include: 

After adding these amendments to your soil, you should wait a few weeks before testing your soil pH again. This is because it takes time for the organic materials to break down and get released into the soil so that the pH level decreases. If you add more organic materials to your soil too quickly, you could add too much and end up with very acidic soil. 

10. Space the Alyssum Seeds 2 Inches (5.08 cm) Apart

When you plant the alyssum seeds, make sure you space them about 2 inches (5.08cm) apart. This will ensure that the plants can grow with enough room. In addition, since alyssum spreads around the planted area, make sure to give it enough space for the future.

When the seedlings grow more than four leaves on the plant, you need to thin them to approximately six inches (15.24cm) apart in all directions so that the plant roots will have enough space to grow. By doing this early on in the alyssum plant’s life, you’ll be able to accommodate its quick growth rate. 

11. Encourage Temperatures Between 55-75 °F (12.7-23.8 °C) 

Alyssum seeds require soil temperatures of between 55 and 75 °F (12.7-23.8 °C) so that they will germinate, as Texas A&M University reports. 

You can use a soil thermometer to test the soil temperature.

12. Mist Them Daily

After planting your alyssum seeds indoors or outdoors, you should mist them daily so that the soil remains moist. When misting alyssum seeds, avoid using the standard spray on your garden hose, as this can be too powerful and will wash your seeds into one area of the garden. This can also cause uneven flowering because there won’t be enough space between the seeds.

When you see the seedlings have started to grow (they should appear within 14 days of planting the seeds), reduce how much you mist your seeds but continue to mist the seeds from above for a few more days.

13. Cover the Seeds With Row Covers During Heavy Rainfall

Since you want to prevent your seeds from being washed away by rain or sitting in soggy soil, you must protect them during heavy rainfall. If you’ve planted alyssum seeds and are expecting heavy rain in your area, you need to protect them from the rain with a row cover. 

I’d recommend plant covers made of ultra-fine polyethylene. These protect your seeds and plants from splashes of water during rainfall while also ensuring that air and sunlight can move through the material to provide your seeds with what they need to grow and thrive. 

If you live in a region with heavy rainfall, planting alyssum seeds on a slope is a bad idea as they’ll get washed down to the bottom of the slope. 

14. Prevent Pests From Attacking Your Alyssum 

When you sow alyssum seeds into the garden soil directly, they can attract pests such as small flea beetles. These can damage your prized seedlings, so you need to ensure that you eliminate them as quickly as possible.

Flea beetles are a common type of garden pest that attacks alyssum and other plants in your garden. As the University of Minnesota Extension reports, they can chew holes in plant leaves, which can result in stunted plant growth. 

Below are some essential tips to eliminate flea beetles from your plants:

Remove Weeds and Organic Matter 

If you have weeds or other organic matter, such as dried leaves, around your alyssum plants, you should remove them. This will prevent the beetles from creating hiding places where they can get a foothold on your plants. 

If you would like to explore your options to keep your garden weed free, check out my article: How To Make a Garden Weed Free (10 Methods)

Plant When the Weather Is Warm 

Not only will planting them when the weather is warm enable them to grow faster, but they’ll be stronger and, therefore, more resistant to damage from pests such as beetles. 

Consider putting row covers around your seedlings to keep the beetles away from them, and ensure you remove the covers before the alyssum plants bloom so that you encourage pollinators.

Treat Plants With Neem Oil 

This natural insecticide effectively removes a variety of garden pests because it contains a compound called azadirachtin that disrupts the insect’s regular bodily functions. 

Here’s how to use it: 

  1. Mix half a teaspoon of neem oil with three drops of dish soap. 
  2. Add the solution to warm water. 
  3. Put the solution in a spray bottle. 
  4. Spray it over your plants. It’s safe for use on seeds and seedlings.

15. Collect the Seeds From Your Alyssum Plant 

Once you’ve succeeded in growing your alyssum plant, you can grow new plants by harvesting the plant’s seeds. When the plant’s pods become brown, you should remove them from the plant and store them somewhere they can dry. 

However, ensure that you pick the pods from the plant before they become too brown and brittle, as the seeds will easily get lost. You should also collect the alyssum seeds when the plant is a bit wet, such as after a rain shower, so that the pods will be less brittle and, therefore, easier to collect. 

Final Thoughts 

Alyssum seeds can be successfully grown in the garden or indoors. However, you need to ensure you follow some important tips so that they sprout. 

These include: 

  • Planting alyssum seeds after a frost when the weather is warm
  • Giving them well-draining soil
  • Giving them temperatures of between 55-75°F (12.7-23.8°C)
  • Misting the alyssum seeds daily until they germinate

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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