Mulching over the top of wildflower seed will stop them from getting enough light to grow. Apply mulch around the wildflowers when they have grown 3-4 inches high. Great mulch options include bark mulch or mixed tree mulch which will stop weeds and hold moisture in the soil helping you to grow a healthy wildflower meadow.
Don’t plant wildflower seeds on top of mulch
Don’t plant wildflower seeds on top of mulch because they won’t be able to reach the soil. Wildflower seeds need to have contact with the soil to sprout and grow well. They can dry out on top of the mulch and won’t grow well.
If you have a very thin layer of straw or sugar cane mulch on the soil as mulch the seeds may still sprout however you will have more success scatter sowing wildflower seeds on bare soil. Then cover them with a thin layer of seed raising mix.
Wildflower seeds won’t grow through thick mulch
Wildflower seeds will not grow well through mulch. If you have a 1-2 inch layer of mulch over your garden, wildflower seeds will not get enough light to sprout through. If you are planting wildflower seeds it is best to leave the soil without mulch to give them enough light to let them grow through.
Do not add mulch back over the area if you want wildflowers to self-seed. They will drop their seeds onto the ground at the end of the growing season, usually late summer and can grow again in spring if the soil is left uncovered.
Covering wildflower seeds – Soil or mulch?
When you plant your wildflower seeds cover them with garden soil or seed raising mix the same thickness as the seed. This will be around 2-3mm of soil over the top. Do not cover your wildflowers with mulch. They won’t get enough light and won’t grow through.
If you want to mulch the area afterwards, let the seeds grow to 3-4 inches and bring sugar cane mulch or bark mulch around the edge of the growing plants. This will keep in moisture and stop weeds.
How to use mulch for wildflower seeds
Rake mulch away from the soil when you are planting wildflower seeds. They like to be planted in an area of soil that gets maximum light. Mulch can block the light that would reach the wildflower seed.
If you cover your gardens with sugar cane mulch or bark mulch then simply use a rake to pull the mulch back and show the soil. Once the flowers grow through, you can move the mulch back around the plants. This will keep the moisture in longer and the weeds down.
If you want your wildflowers to re-seed themselves each year, then you will need to keep the mulch off and the soil bare. That way the seed scan drop onto the ground and will be exposed to light helping them to grow through.
Mulch will naturally form in your wildflower garden as parts of the wildflower plants naturally die off. Like in nature, leaves will fall to the ground covering the soil and forming a natural mulch.
Wildflower seeds won’t grow through mulch the next year
If you place mulch under your wildflowers the seeds that will drop the next year are not likely to grow. The mulch acts to stop weeds from growing through by blocking light and it will do the same for your wildflowers. To let your wildflowers self-seed naturally year to year, do not place mulch underneath them.
Plant your wildflowers close together so that they cover the area thickly and you won’t need to use mulch. If you have bare patches of soil, scatter sow annuals or buy small seedlings to plant in the gaps.
How to choose wildflower seeds
If you want to grow a native wildflower mix then contact your local seed savers group to get seeds local to your area. If you are keen just to grow a range of flowers that grow like a meadow, then you can get wildflower mixes from your local hardware store or garden center.
Wildflower seed mixes can contain around 20 different species of flower. They will grow at different heights and speeds to fill the space giving insects and birds protection. The mix that I recently planted contained flowers that attract pollinators like Poppys, Aster and Lavender.
Most wildflower mixes will have both annuals and perennials. That means that you will get beautiful flowers from the annuals in the first season, while the perennials will continue to grow and flower into the next year. You can then sprinkle more annual seeds between the perennials year to year to add extra color.
When to plant wildflower seeds
Plant your wildflower seeds in spring. If you plant your seeds in May, you can expect to see flowers by the summer. You can also plant wildflower seeds in Fall if you live in an area with a mild winter or if you have a green house to protect your seeds. You can also buy mini propagation kits to protect your seeds from the cold weather.
I have recently planted my wildflower seeds in Fall (Autumn here in Australia) because I live in an area with a mild winter and warm, rainy summer. We have perfect growing conditions to raise seeds from Fall into winter in Sydney and winter does not get too cold. If you live in a frosty or snowy area, wait until spring to sow your windflower seeds.
How to sow wildflower seeds – Scatter Sow Method
To sow wildflowers straight in your garden beds use the scatter sow method. This is where you gently sprinkle seeds straight into your garden and they can grow up like a beautiful wildflower meadow.
What you will need
- Sandpit sand
- Seed raising mix
- Wildflower seeds
Pick a nice open sunny spot in your garden that is not under any trees. You don’t want your wildflowers competing with large trees to get water.
Rake back any mulch and expose the soil. You will want to start with a space that is at least 2 feet by 2 feet and you can go as large as you have space for.
Rake the surface flat and let the rake make small holes in the soil. When you scatter the wildflower seeds over the soil they will fall into the holes.
Mix your wildflower seeds with sandpit sand if you have some. This step is optional but mixing the seeds with sand will make it easier to scatter them and get an even layer.
Gently scatter the seed and sand mix over the top of the raked soil as evenly as you can.
Grab handfuls of seed raising mix and scatter it on top of the seeds. You can also use sieved garden soil if you like. To do this take 1-2 shovels of your garden soil and run it through a wire or plastic sieve. This will remove any coarse pieces before putting it on top of the seeds. This will give the seeds a easy path to sprout through the soil.
Make sure that you only cover the seeds very lightly with the seed raising mix or garden soil. Wildflower seeds only need a very small amount of soil to cover them. This will stop the seeds from blowing away and to deter birds from eating the seeds.
Water the seeds in using the shower setting on your hose nozzle. Make sure you spray the seeds gently so you don’t wash them away.
Keep the seeds moist until you see them sprout through the ground. You will need to check them everyday for the first 1-2 weeks and water them when the top soil gets dry. After they have grown through they should send roots deeper into the soil to reach moisture deeper down.
Do not cover wildflower seeds with mulch. This will stop them from being able to reach the light and grow through. Wildflower seeds sown thickly should cover the area after they have grown so there will be no need to mulch. They will form a thick cover like a blanket and protect the soil from drying out.
Planting wildflower seeds in pots
You can plant wildflowers in pots first and then plant them out into your mulched garden or leave them in their pots to grow. Scatter sow the seeds on top of seed raising mix and gently cover them with more seed raising mix. Keep the wildflower seeds moist until they grow to 3-4 inches and then you can plant them out in your garden.
This year I have planted a wildflower mix in a large pot so that I can let the plants get bigger before I put them in my garden. I only have a small space so I will plant groups of wildflowers in patches between the mulch.
I always keep my garden covered in mulch to keep weeds down and the soil moist. I will then move the much back around the wildflower clumps.
The wildflower seed mix I have chosen contains both native flowers and non-invasive species from other countries. The main purpose is to attract more pollinators to my garden to support the local bee and dragonfly population. They will add to the other bee-attracting flowers I already have in my garden.
There are many ways to choose your wildflower mix. Think about whether you want color, if you are improving native habitat or attracting pollinators. Choose a mix that is right for your climate and for best results, plant them in spring as the weather starts to warm up.
I always find success by planting my seeds in pots first and then planting out when they are seedlings. That way I simply move the mulch back in a small area and plant the larger plant in.
Mulching tips for wildflowers – FAQ
Don’t use any mulch on top of your wildflowers when you are waiting for the seeds to grow. Once the plant is established the best mulch for wildflowers is a mixed bark mulch, sugar cane mulch, pea straw mulch or straw mulch.
A mixed bark mulch will benefit the soil as it has both green and brown materials which will be broken down by the microbes and worms in your soil. This will add nutrients to your soil over time, keep in moisture and stop weeds. If you want your wildflowers to self seed, keep the area clear of mulch so the seeds can drop onto the bare soil.
Mulch placed over the top of wildflower seeds can stop them from growing altogether however adding mulch around your plants can help them to grow quicker and stronger. Mulch improves soil and stops weeds so it will stop the competition to your wildflowers. It can also make it easier on you as you won’t have to go out and pull out as many weeds from around your wildflowers.
To allow wildflowers to self-seed, keep the mulch away from their base and let them drop seed on to the soil directly. Do not add mulch over the area where the seeds would have dropped as this will block the light and stop the seeds from sprouting the next year.
Mulch is building up the natural worm colonies in my soil and improving it over time. I am creating a healthy microbiome in my soil by using mulch and always like to keep soil covered with bark mulch or sugar cane mulch, even around wildflowers.
Wildflower seeds will not grow through mulch as the mulch will stop the sunlight from reaching the seed. Keep the soil clear of mulch until the seeds emerge which will allow them to grow leaves, photosynthesize and grow into healthy wildflower plants.
Do not put mulch over planted seeds as the mulch can stop them from growing well. It might seem like a good idea to add mulch over the top to prevent weeds but this will also stop your seeds from growing, Wildflowers are particularly sensitive to mulch so keep it off of the top of your seeds.
You can sprinkle wildflower seeds over clear, raked soil but it is best to sprinkle over a light layer of seed raising mix to cover the seed. This will stop them from blowing away, help to keep them moist and help to stop birds and bugs from eating them.
Mulching wildflower seeds – Summary
Wildflowers are a fantastic addition to any garden but remember not to mulch over seeds. Let your wildflower meadow grow and mulch around the edges to keep the plants moist and weeds away from the outside. If you plant the seeds close together they will form a blanket and stop weeds from growing between.