Did you know that quite a few plant species require direct light to germinate? These seeds are known as “photoblastic,” and if they’re covered with soil rather than surface-sown, they’ll likely fail to thrive.
As you’re planting your seeds each year, you might find that some fail to germinate more often than others. It might be that you’re planting them too deep.
Below are 24 of the most common light-dependent germinators you may come across in your gardening or homesteading endeavors.
Vegetables
The vegetables listed below produce tiny seeds that must be sown on or near the soil’s surface to thrive. If they’re planted too deeply, the sun’s heat and light will not activate their germination.
1. Arugula (Eruca vesicaria)
With arugula, your best bet is to scatter significant amounts of seed over the surface of a prepared bed. Then, once they’ve grown a few inches in height, thin them out so there’s about six inches of space between them.
Eat the sprouts that you’ve thinned out, and let the rest of the plants grow to maturity.
2. Carrots (Daucus carota)
Although the seeds of many other species on this list need to be surface-sown, teensy little carrot seeds do best if they’re covered in a very fine blanket of loose soil or compost.
These seeds do require light to germinate, but that light can be filtered through their protective layer. Furthermore, that layer may also keep insects and birds from eating the seeds before they can sprout.
3. Celery (Apium graveolens)
Celery seeds also need light to germinate, but they can be picky about the type of soil they’re sown onto.
Since this plant needs a lot of water to thrive, your best bet is to use a seed-starting mix with coconut coir in it—this will provide those seeds with the regulated moisture they need to sprout.
After you scatter the seeds on the dampened soil’s surface, press them in lightly and let them do their thing.
4. Lettuce (Lactuca sativa)
Just like celery seeds, tiny little lettuce seeds do best when they’re scattered on the soil’s surface, rather than pushed down into it. If you’re sowing directly outdoors, however, be aware that you’ll likely lose about two-thirds of your seeds to bird and insect predation.
As such, sow three to four times as many seeds as you think you need, and simply thin out maturing plants as they grow. Or, you can cover your crops with cloth.
Read our essential guide to growing lettuce to learn more about how to cultivate this delicious, versatile vegetable.
5. Purslane (Portulaca oleracea)
This lovely, succulent perennial vegetable also creates mini seeds that require light to germinate, but once established, it’ll keep coming back indefinitely.
Its seeds like consistently damp soil, so broadcast them in an area that’s well-draining, but won’t dry out too quickly. They’ll do best in direct sunlight, and germinate within about a week.
6. Stinging Nettles (Urtica dioica)
I grow stinging nettles around the edge of my land for both food and property barriers, and their seeds are some of the tiniest I’ve ever come across.
Since these also require light to germinate, simply rake the soil in an area where you’d like to cultivate them, water it well, and broadcast the seeds all around. Keep this area consistently moist and the seeds should sprout within seven to ten days.
Culinary Herbs
These are some of the most popular and most commonly cultivated kitchen herbs. You likely already have many of them growing in your garden, but if you’re keen to grow more from seed rather than purchased seedlings, you’ll have to ensure those seeds get plenty of direct sunshine to thrive.
7. Basil (Basilicum spp.)
If you’d like your basil plants to thrive, press the seeds into the soil when you sow them but don’t cover them up.
These tiny seeds need a significant amount of heat and light to germinate, and a blanket of soil may prevent them from sprouting. Just ensure that you’re well past your area’s last frost date before sowing and they should do just fine.
8. Chives (Allium schoenoprasum)
Who doesn’t love chopped chives on their baked potato or smoked salmon and cream cheese bagel? These tasty members of the onion family scatter their seeds when they mature. You can collect them just before the seed casings split open and sow them around.
Since they need light to germinate, simply scatter them on a prepared surface, water them well, and watch them grow.
9. Dill (Anethum graveolens)
Although dill seeds are larger than some of the others on this list, their seed casings are so thin that they need direct light to germinate. As such, simply scatter them onto damp soil or press them in very lightly.
If you feel that you need to cover them so they don’t blow away or get eaten by local wildlife, scatter soil over them quite sparsely: no more than 1/8″ thick.
10. Sage (Salvia spp.)
Depending on the Salvia species you’re planting, sage can be a culinary, medicinal, or ceremonial plant. Regardless of its purpose, however, know that its seeds are light-dependent and thus can’t be planted deeply.
You can either surface-sow them on prepared, well-draining, slightly sandy soil, or press them in and scatter light, seed-starting soil over them in a thin coating.
11. Violets (Viola sp.)
These beauties also need direct light to germinate, though a few species do well if covered lightly with soil. Your best bet is to check the directions for the particular species you’re planning to grow so you can offer them optimal germination conditions.
As a general rule, however, surface-sown Viola species seeds will be much more likely to thrive than buried ones. Learn more about growing violets in our guide.
Medicinal Herbs
The plants below are cultivated primarily for medicine, but they’re also invaluable for attracting pollinators. As such, be sure to interplant them with compatible food crops, or use them in perimeter beds to beckon birds, bees, and butterflies over.
12. Anise Hyssop (Agastache)
Not only do agastache (aka anise-hyssop) seeds need light to germinate, but they also require cold stratification to thrive properly.
As such, it’s best to either plant them in the autumn so they can sleep all winter before sprouting in springtime or sow them before your last spring frost date so they get enough of a chill to trigger germination.
13. Bee Balm (Monarda spp.)
Monarda seeds also need cold stratification, so you should either plant them in the fall or well before the last frost. You can also mix them with some moist sand and keep them in the fridge for one to two months before scattering that mixture outside.
Since these seeds are light-dependent germinators, simply scatter that prepared seed onto nearby soil, and watch it explode into scent and color.
14. Catnip (Nepeta cataria)
Catnip seeds do best if you soak them for 24-36 hours before sowing directly onto the soil’s surface.
They (like many others in the mint family) need light to germinate, but you can either broadcast them onto the soil or cover them very lightly with a seed-starting medium, especially if you’re in a particularly chilly climate.
Additionally, since mint plants are known to spread vigorously, you may wish to keep these plants contained within an isolated section or large pot/grow bag.
15. Immortelle (Helichrysum italicum)
This lovely plant, commonly referred to as “strawflower,” has startling healing abilities. It’s a Mediterranean herb that thrives in well-draining, sandy soil and a ton of sunlight.
In fact, its little seeds need direct light to germinate, or they won’t sprout. Simply scatter them on top of pre-dampened soil and let the sun do the rest.
16. Lavender (Lavandula spp.)
While lavender seeds also require light to germinate, it’s important to note that they won’t thrive well in soil that’s too rich or too wet.
They do best in well-draining, sandy, even gravelly soil that’s close to the soil in the Mediterranean and Eurasian areas where it originated. After a rain shower or light watering, scatter your lavender seeds in an area where they’re likely to thrive, and let them be.
17. Mugwort (Artemisia vulgaris)
Whether you’re growing mugwort for medicine or as a flavoring agent, know that the seeds won’t thrive well if they’re planted rather than surface-sown.
These seeds are also light-dependent germinators, and shouldn’t be planted more than an eighth-inch deep. Ideally, you’ll scatter them over raked, well-draining, loamy, and slightly acidic soil, and let them sprout without too much interference.
18. Mullein (Verbascum thapsus)
Many people are startled to discover that a plant like mullein, which can grow so very tall, produces such tiny seeds. They’re only one or two millimeters in diameter, and as such need to be surface-sown for direct light to germinate.
Mix them with sand if desired to help with dispersal, and scatter widely in any area in which you’d like them to grow.
19. Poppies (Papaveroideae sub-family)
Poppies are an absolute delight in any garden, though the laws in your area may limit their cultivation. The Papaveroideae sub-family includes species such as:
- Breadseed poppies (Papaver somniferum)
- California poppies (Eschscholzia californica)
- Corn/field poppies (Papaver rhoeas)
All of these flowers have seeds smaller than the head of a pin. Scatter them onto prepared soil for direct light to germinate, and let them do their thing. Most are biennial, so they should keep coming back every other year.
20. St. John’s Wort (Hypericum perforatum)
This mood-uplifting herb is essential for any herbalist’s garden, and is ridiculously easy to propagate. Its tiny seeds need to be scattered atop the soil, so once you’ve prepared the site you’re eyeing, simply broadcast them as you see fit, water them in, and let the magic happen.
21. Yarrow (Achillea millefolium)
Whether you’re growing yarrow as a medicinal herb for your apothecary cabinet, or as a companion species to attract bees and braconid wasps, ensure that you surface-sow its seeds rather than burying them.
Although some other species on this list do best with a light scatter of soil on top of them, yarrow seeds require direct light to germinate rather than filtered through compost.
If you’re interested in learning more about homestead herbal medicine, read our article for a comprehensive book list to help get you started.
22. Savory (Satureja hortensis)
Related to mint, thyme, and marjoram, summer savory doesn’t get the same attention that its cousins do. But its a worthwhile herb to keep around, especially if you adore bright, herbaceous flavors.
The tiny seeds should be gently pressed into the surface of the soil and kept moist until germination.
Additional Species
Although these plants are edible, they’re characterized as proto-grain and seed plants rather than vegetables. They’re also quite versatile on the homestead and are multi-purpose plants (e.g., for greens, seeds, and/or oil, depending on the species).
23. Amaranth (Amaranthus)
I made the mistake of planting amaranth seeds when I first started gardening, and got immensely frustrated when they only had a five percent germination rate. These teensy little seeds need warmth and direct light to germinate, so be sure to sow them in loose, loamy soil for optimal sprouting power.
24. Chia (Salvia hispanica)
Did you know that the seeds you use to create delicious chia pudding are from plants in the mint (Lamiaceae) family? As with many other mint family herbs mentioned earlier, chia’s tiny seeds need to be sown on or near the soil’s surface in order to thrive.
You can either scatter them on prepared soil for the light to germinate, or cover them very lightly with loose, lightweight compost so the light can filter through to the seeds.
25. Flax (Linum usitatissimum)
Homesteaders love flax because it’s such a multi-purpose plant: good for seeds and oil as well as fibers for spinning into linen. Flax seeds also need light to germinate, but can be either surface-sown or pressed into the earth and covered with a light coating of loose soil and compost.
Notes on Seeds that Need Light to Germinate
You’ll likely notice that these seeds have certain traits in common, namely being quite tiny and having thin, light-permeable seed coats. Although these attributes are shared by many seeds that require light to germinate, they aren’t omnipresent.
Always check your seed packets for information on how to plant a particular species, or consult your local botanist, herbalist, or garden center associates if you need additional help.
Because you’re sowing seeds right on the surface, birds and other critters might steal them. Sow more seeds than you think you need or cover your crops with fost cloth or something similar until the seeds germinate.
