So You Planted Seeds Days/Weeks Ago and Nothing's Come Up, Huh?

Seeds are pretty incredible little things, but they're also incredibly picky. They're like Goldilocks in the story about the three bears; they need everything to be just right for them to grow.

They won't, for example, wake up until the weather is just right—not too hot, not too cold, but just in their ideal temperature range. Make the mistake of planting seeds when it's too cold, and those seeds will wait until it warms up... or they'll rot in the soil long before it's time for them to germinate.

If, on the other hand, you try to plant them when it's too hot outside, they might rear their little plant heads, only to sink back down when they realize the sun is just too bright for their liking.

Basically, to get a seed to sprout successfully, you need to get the planting depth, the water delivery, the timing, and the soil temperature just right. Let's look in more detail at the reasons the seeds you planted might not be coming up to say hello.

You Planted the Seed Way Too Deep

I know it's tempting to dig a nice, deep hole whenever you have a trowel in one hand and a seed packet in the other, but one of the main reasons seeds don't sprout is because they were simply buried too deeply. Picture a seed germinating and sending its first little stem up to look for sunlight, only to encounter more and more soil.

I like to think of seeds as nature's Swiss army knives, each filled with so many different useful things the plant will need. But this Swiss army knife unfortunately doesn't come with anything to help the baby plant claw its way through the soil to make it to the surface. Most seeds pushed way too far underground will wither and die before ever reaching the soil surface. Even if a seed's little shoot finally makes its way to the top, the baby plant will be worn out. Whatever life is left to it at this point will have begun in distress.

A seed only needs to be planted to a depth that's about twice its width. So if a seed is 1 inch in diameter, plant it about 2 inches deep. But what about those seeds that are so tiny it's hard to measure how wide they are? How do you double almost nothing?

For seeds less than an inch in diameter, you don't even need to dig a hole at all. Simply place the seeds over loosened and leveled soil, and then lightly sprinkle soil or compost on top. This is how you'll plant seeds for most leafy greens, from spinach to spring mix to arugula. These seeds also like a little sunlight on their coats as they germinate, so they like being right up near the surface.

Using a dibber, like the one pictured below, for larger seeds is a great way to check how deep you're making each planting hole.

You Stopped Watering Way Too Soon

Water is necessary for seeds to wake up from dormancy. They need to be exposed to wet soil for days so that their tough outer layer will finally let some water through. That water tells the little plant embryo inside that it's time to wake up. The seed will swell with more and more water until it's expanded so much it can't take it anymore. It just has to burst open (sprout). If you water your seeds daily and then suddenly withhold water, seeds that have just begun to swell will shrivel up.

Picture a bunch of seeds that have fallen from a flower head at the end of a growing season. Those seeds will sleep through the long, dark months of winter. When spring arrives and the snow begins to melt, water will trickle down and keep the soil around those seeds nice and moist. Each day, the seeds absorb more and more of the snowmelt, until, finally, the seeds germinate.

In nature, the slow snow melt provides regular and ever-present moisture for seeds throughout their entire germination process. In your garden, you might need to step in and do the work of Mother Nature. Imitate melting snow. While the soil doesn’t need to be soaking, it should be a little moist to the touch and never allowed to dry out completely before you see the first signs of green popping up.

While we're on the topic of watering, here's your reminder to take care when watering newly planted seeds, especially the teeny tiny ones. Heavy watering (and heavy rainfall) can displace seeds. The best way to water seeds sown outdoors is overhead with a spray head that allows the water to evenly disperse over the soil’s surface instead of pooling in any one spot. If you've started seeds indoors, it's best to water from the bottom or spray the top with a water bottle.

The Soil Temperature Isn't Right for the Seed to Sprout

Remember Goldilocks with the porridge? Seeds are also very sensitive to temperature. It's actually wired into their DNA to only sprout when soil temps are within a certain range. When the soil is too cold, seeds do the equivalent of crawling under the blankets and hiding. They'll basically just sit there until the temperature is within their preferred range.

This makes a lot of sense if you think about it. Seeds are often scattered by the wind or animals and land somewhere when the season is not right for them to start growing. They need to last throughout the year (or at least the winter) and not sprout until just the right time. 

Different seeds sprout at different temperatures. Tomato seeds, for example, sprout when the soil is nice and warm, while carrot seeds like cooler soil. If you're starting seeds that like warm soil indoors, you might have the best results using a heat mat to get them started. Electric heat mats warm the soil to about 10°F above room temperature—perfect for initiating seed germination for warm and hot season plants.

If you're direct sowing seeds, use a simple soil thermometer to ensure your soil temperature is in the ideal range before planting. If needed, there are a couple tools that can help regulate your soil temperature and extend your growing time a bit. During the transition from cold season to cool season, for example, you could use a frost cloth or cold frame when you first plant to protect young seedlings from frost. If you're hoping for seeds to germinate at the end of your warm season before the transition into your cool season, you could use a shade cloth to cool the soil.

Your Seeds Just Need More Time

Gardening is sometimes an exercise in patience. If your seeds have been taking their sweet, sweet time germinating, they might just be slow sprouters. Along with so much other data like how tall and wide the plant should grow, what shape the leaves will be, how the plant will find food and fend off predators, seeds have a certain number of days that they need to sit in wet soil in just the right temperature before they'll sprout built into their DNA.

There's no rushing this process. Check the number of days till germination on the back of the seed packet. Remind yourself that good things take time.

Your Seeds Are Losing Viability

Seeds should be planted as close to their packaging date as possible. Seeds can remain viable from one to six years after they're packaged, depending on what type they are, but you'll find the best success rate when you plant fresher seeds.

You probably would have noticed mold or rot on seeds if they'd gone bad before you planted them, but seeds can certainly degrade over time. That just means the likelihood they'll ever germinate decreases. Seeds can also die if they're not properly stored, especially if they're exposed to too much heat or cold. Even if they don't die, they'll lose viability every time they experience a less-than-ideal condition.

Make sure you store your seeds properly to help them stay viable as long as possible. If you're past the typical germination window and nothing's come up, you might want to buy a fresh package of seeds.

How to Test Whether Seeds Are Still Good

Before you plant seeds that you've been storing for more than a year, it's a good idea to run a simple germination test to learn the odds of these seeds sprouting in your garden (assuming you get the planting conditions right).

HERE ARE THE STEPS TO TEST GERMINATION RATES:

• Spread out 10 of the seeds on a damp paper towel.
• Roll up the paper towel and place it inside a plastic bag.
• Place the bag in a warm spot.
• Feel the paper towel every couple of days and spray it with a water bottle as needed.
• After 7 to 10 days, check to see how many of the seeds have sprouted.

Multiply however many seeds have sprouted by 10, and that's your germination rate (2 seeds equal 20 percent, 5 seeds equal 50 percent, etc.). If your germination rate is less than 70 percent, you can always still plant those seeds in your garden—just sow them more heavily than you normally would to increase the likelihood of those seeds becoming seedlings. If your germination rate is less than 50 percent or so (or if the seedlings that emerged seemed stunted), I recommend starting over with fresh seeds.

Seeds that sprouted during your germination test can, of course, carefully be transplanted to your garden.

Time to Plant Some More Seeds

If you filled your garden with seeds that never sprouted, you're in good gardening company. We've all been there. Maybe now you've pinpointed the issue or learned a little planting lesson so that you'll have more success next time.

Now, get out there and plant some more seeds! My gardening motto is never stop planting, never stop learning.

Thanks for being here and bringing back the kitchen garden with me!