We’ve all been there. You find this variety that you have to have in your garden (poppies, anyone?) and you open the seed packet to find…dust? Seeds can’t possibly be that small, can they?
Before you give up on that dream to have a field of poppies, know that there are several tricks to make sowing small seeds easier. Read on to learn how you can use something as simple as sand or as involved as homemade seed seed tapes to put you on the path to the garden of your dreams.
Why Smaller Seeds Need A Little Extra Attention
In nature, small seeds are generally produced in larger quantities than their larger counterparts. This is because small seeds have a much lower germination rate than bigger seeds. So wild plants produce small seeds in bulk to offset the low germination rate.
Small seeds also tend to have a thinner seed coat, which makes sprouting faster. But this design, in conjunction with the lesser food stores that are available to small seeds, makes the seed itself more susceptible to the elements like temperature, moisture, and wind.
While most large seeds like peas, beans, and squash can be planted directly in the ground come spring, small seeds do best when started indoors – it gives the tiniest seeds the upper hand in germination and the smallest seedlings a better chance at surviving transplant shock.
7 Tips For Sowing Small Seeds
The easiest way to sow small seeds is to mix your seeds with a little bit of sand. The sand makes even the smallest seeds easier to handle, and has the added benefit of marking where you sow the seed.
There’s no magic recipe here – simply mix a pinch of seed with a couple tablespoons of sand. Then, either broadcast the mixture over the planting area or use a saltshaker to sow in a more constrained space.
A similar technique to mixing seed with sand, some gardeners choose to use cornmeal simply because it’s readily available in their kitchen cabinets.
It’s worth noting though – while cornmeal will quickly break down in the soil, sand doesn’t. Sand is a great additive to low spots or in soil that needs better drainage.
Why not kill two birds with one stone and sow small seeds with sand, all the while improving the consistency of your native soil?
3. Seed Tape
Many gardeners use seed tapes to make the task of sowing small seeds that much easier. You can buy pre-seeded tapes online.
However, it’s just as easy to make your own seed tapes! If you do make your own, you can choose what variety of seeds you’re using and you can set the spacing – all while saving money.
Seed tapes are perfect for seeding outdoors, but this technique doesn’t really work for seeding in trays or flats. The University of Illinois Extension has a great video on how to use seed tapes, which I will summarize below.
To make homemade seed tape, you’ll need a roll of toilet paper or paper towels. Toilet paper is preferred by most gardeners as it’s smaller and easier to work with.
Unroll the toilet paper to the length of your garden rows, or to the length of your raised beds. If that’s too long to comfortably work with – or if you don’t want a whole row to be one type of seed – then break the tape into smaller pieces and just use multiple tapes on each row.
You can either make your tape to use the same day you seed, or you can prep a seed tape to use at a future date. To use a seed tape the day of, create a divot or a small trench in the garden bed.
Line the trench with the roll of toilet paper. Then, sow your seeds at the recommended spacing on the back of the seed packet.
If you’re prepping seed tapes ahead of time, you’ll want to make a “glue” to attach the seeds to the paper. Make a simple, biodegradable glue using 1 part water to 1 part flour.
Next, unroll the paper to the desired length, and have your seeds on hand. Put a dab of glue at the recommended spacing for that variety, and sprinkle a few seeds at every dab.
Once you’ve filled out your seed tapes, roll the tape back up and store it in a dry space until it’s time to plant. All you have left to do is plant the seed tape as described above.
Try to keep the tape out of light and moist areas, as the seeds may sprout prematurely. If your seeds sprout before they’re supposed to, plant the tapes in an open seed tray and transplant them outside at the appropriate time.
4. Seed Gel
Making seed gel may be the most involved of these small seed-sowing hacks, but it could be a fun project for the gardener who has time for it. Just be sure that your planting area is already prepped before you start this project, as you’ll want to sow these seeds immediately (seeds don’t store in seed gel like they do in seed tapes!)
To make seed gel, you’ll need a cookpot, a stovetop or hot plate, cornstarch, and water. Mix a tablespoon of cornstarch with a cup of water and bring to a boil for a minute. Allow the mixture to cool, and you have gel that looks something like a kid’s school project.
Once the gel has cooled down to room temperature, transfer it to a plastic Ziploc bag. Add however many seeds you want sown and stir thoroughly. Combine several varieties together if you want a mix, or stick to one variety at a time – it’s up to you. Once the seeds are in the gel, seal the bag shut.
Cut the corner off the plastic bag and you’re ready to sow small seeds! Squeeze the bag to force the seed gel out and onto the soil.
Seed gel doesn’t guarantee even spacing like seed tape does, but it still works to spread small seeds over a space without too much clumping together.
Another simple trick for sowing small seeds is to use a toothpick, pencil, or plant label. Moisten the end of your preferred utensil, and the tip to pick up one or two seeds at a time.
This technique is best for gardeners who have plenty of time and patience, or for those tiny seeds that need to be started indoors in flats.
6. Pelleted Seed
Another option is to buy pelleted seeds. Pelleted seeds are generally coated in clay or another biodegradable substance to make them easier to handle. They might also be brightly colored to make the seeds easier to see.
Sometimes pelleted seeds are also treated with a fungicide, so read the product description thoroughly before you buy pelleted seeds, just to know what exactly you’re getting. You may want to use gloves with pelleted seeds just to be safe.
7. Hand Tools
If you sow a lot of small seeds every year, you might want to invest in a few hand tools to make the job easier.
Johnny’s Seeds, a popular seed company, makes a handheld seeder that makes sowing small seeds in flats easy! This simple seeder has five different adjustable settings that allow you to control what size seed to use and how much of that seed. Simply open the cap, add your seeds, and select the appropriate setting. Suddenly sowing small seeds becomes a breeze!
While much more of an investment, vacuum seeders make quick work of the chore of seeding. Vacuum seeders usually come with several interchangeable plates, each designed to fit one of the common seed tray sizes–50, 72, or 128-cell trays. The seeder will be attached to a vacuum.
Prep your seed tray with moist potting soil ahead of time, then fire up the vacuum seeder!
Make sure that the vacuum is off, turn your seeder so that the plate is facing up, and empty the seed packet onto the plate. Turn the vacuum on, and the air suction will pull seeds to the holes in the plate that align with the seed tray. You may need to shake or tap the seeder to move the free seed across the plate until they are held in place.
When all the seeds are in place, you can then flip over the seeder to align it with the seed tray. Now flip a switch to cut off power to the vacuum, and all the seeds will drop in their appropriate place.
Continued Care Of Small Seeds
Small seeds, by design, require a little more aftercare than larger seeds. Whether you start your seeds indoors or direct sow in the garden, take these few extra measures to ensure that even the smallest seeds will sprout into healthy seedlings.
1. Use A Heat Mat
Heat mats aren’t just for small seeds, but smaller seeds certainly benefit from the extra germination boost. Heat mats are designed to sit underneath a standard-sized seed tray and warm the soil to a predetermined temperature.
2. Use A Humidity Dome
These plastic lids that fit over a standard-sized seed tray create microclimates that help small seeds germinate faster. While not necessary for germination, humidity domes do capture heat and moisture that small seeds need to sprout.
Small seeds usually need to be started sooner than their larger counterparts. This allows the seedlings ample time to grow before they are strong enough to be transplanted outside.
Read more about humidity domes here.
3. Cover With Vermiculite
Unlike large seeds, most small seeds require light to germinate. After small seeds are sown, take care not to bury them under too much soil, or you’ll never see seedlings emerge.
However, you don’t want to leave the seeds bare on the surface of the soil either, as they might get swept away by wind, water, or animals.
Rather than cover your small seeds with soil, dust them with a light covering of vermiculite. Available at most garden supply stores, vermiculite is a natural mineral mined from volcanic rock.
Horticultural vermiculite is flaky and lightweight, perfect for providing seedlings with some protection while still allowing light to seep through. Vermiculite adds aeration to the soil and helps retain water and nutrients close to the sprouting seeds.
A cheaper alternative to vermiculite is sand. Sand provides seeds with some protection but isn’t as dense as soil. However, sand doesn’t retain moisture like vermiculite does.
For further reading on vermiculite and other common potting soil ingredients, check out this article.
4. Bottom Water (Or Mist)
Don’t overhead water small seeds – you run the risk of scattering them around in the seed tray, or worse – washing them away. Instead, either use a watering wand set on the misting setting, or use a clean spray bottle – one that’s never been filled with anything other than water.
Or, you can choose to bottom water small seeds and delicate seedlings. To bottom water, fill an open tray (without holes) with a couple inches of water and place the seedling tray in the bottom tray. Allow to sit for 30 minutes, and the remove the seedling tray and dump any excess water.
Until seeds germinate, you’ll want to keep the soil moist, but not soaking wet. After seedlings have sprouted, allow the soil to dry out between waterings, to help prevent diseases like root rot and damping off from developing.
5. Protect From The Sun
Any seeds can suffer sun damage, but small seeds are more susceptible as the seed coat isn’t as thick as it is in larger seeds. To help protect small seeds from sun damage, you can use a shade cloth in your greenhouse, or you can cover individual seed trays with a webbed bottom flat to block out about 50% sunlight.
The best way to protect small seeds from sun damage is to avoid watering in the middle part of the day. Water in the morning or evening to avoid scorching small seeds and delicate seedlings.
Read this article to learn more about what tools you can use to protect your seedlings from the sun.
6. Thin Seedlings
Small seeds are often multi-sown for a variety of reasons – the germination rate isn’t as high, for one, and it’s difficult to individually sow small seeds, for another. Whatever the reason, once seedlings sprout, they will eventually need to be thinned.
Thinning seedlings is a difficult but necessary chore. It’s no fun to intentionally remove healthy seedlings, but seedlings sown too thickly will compete for water, nutrients, and light until there isn’t much left of a crop at all.
It’s counterintuitive, but for your seedlings to thrive, you must carve out space for them – even at the cost of other seedlings. Thin out the weakest seedlings by pinching or cutting them off at the base of the plant.
Don’t pull the seedling out by the root, as that will disturb the other seedlings’ roots as well. If you’re growing edible plants (like lettuce, brassicas, or peas), save the thinned seedlings to eat them like microgreens on your sandwich or salad!
For an in-depth look at how to thin seedlings, read this.
7. Bump Up Seedlings
If you start your small seeds in 128- or 200-cell seed trays, they may become rootbound before they are ready to be transplanted outside. To check if it’s time to bump seedlings up to a bigger pot, lift the seed tray up and check the bottom.
Can you see roots growing out of the holes in the bottom of the seed tray? If so, it’s time to transplant those seedlings into bigger pots.
So many of the loveliest flowers and tastiest vegetables come from the smallest seeds. While sowing small seeds can seem like a daunting task, there are a few tools and tricks to make the job a little easier. Go find the smallest seeds you can, and have fun with it!
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P.S. If you want to read some of my most popular posts, please check out the “Best of GreenUpSide” page here. Enjoy!
“Tricks For Sowing Small Seed,” YouTube, University of Illinois Extension, 23 May 2012, https://m.youtube.com/watch?v=kBedwKpuW10.
About the author:
When not writing content or growing flowers in her native Virginia, you can find Sarah hiking a long-distance trail deep in the woods. Follow along with Sarah’s adventures at http://sarahcolliecreative.com.