Get Ahead of Your Garden: Start Seedlings

By Shelley Stonebrook
Published on August 26, 2016
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Heirloom enthusiasts interested in rare varieties will love the benefits of start seeds early.
Heirloom enthusiasts interested in rare varieties will love the benefits of start seeds early.
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You can save money by making your own seed-starting mix.
You can save money by making your own seed-starting mix.
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Start tomato seeds 6 to 8 weeks before your average last frost date.
Start tomato seeds 6 to 8 weeks before your average last frost date.
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Use whatever is available for pots: egg cartons, egg shells, even toilet paper rolls!
Use whatever is available for pots: egg cartons, egg shells, even toilet paper rolls!
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Water seedlings using a spray bottle or by adding water to the bottom trays holding the pots.
Water seedlings using a spray bottle or by adding water to the bottom trays holding the pots.
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It's good insurance to plant two seeds per container and thin later using scissors.
It's good insurance to plant two seeds per container and thin later using scissors.
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Keep seedlings at a consistently warm temperature — around 70-80 degrees F is a good range.
Keep seedlings at a consistently warm temperature — around 70-80 degrees F is a good range.

Every gardener has particular moments that are his or her absolute favorites of a growing season — moments like receiving a much-anticipated seed order in the mail, harvesting the first of the spinach in spring, cutting into a ripe melon, or talking with fellow gardeners about successes and failures.

Me? I love the moment when my tomato seeds turn into strong seedlings, and I can brush my hand across the tops of the plants growing indoors and smell that glorious fresh-tomato smell. It feels like a wonderful form of cheating getting to breathe in that lovely smell long before the heat of summer.

Seed-starting is an enjoyable process that affords many benefits to the home gardener. Here are 10 reasons to start your own garden seeds and 10 tips to help you achieve seed-starting success.

Why start your own seeds?

Endless Varieties. OK, maybe not endless. But your variety options will exponentially increase when you decide to start seeds at home. When shopping for starts at a garden center (or, more limiting yet, the garden section of a big-box store), you’ll typically find the same boring varieties over and over again: Big Boy tomatoes, Early Girl tomatoes, California Wonder peppers, maybe some hybrid broccoli. But in home seed-starting, the sky’s the limit. You can try all kinds of unique varieties, and match your seed starting to your gardening goals, such as wanting compact plants, out-of-this-world flavor, high yields, or disease resistance.

More Heirlooms. This goes hand-in-hand with No. 1, but it’s worth noting: Heirloom enthusiasts interested in trying all kinds of cool, rare varieties will love the advantages of having an efficient seed-starting setup at home.

Save Money. Purchased transplants aren’t cheap. One packet of seeds generally costs less than a single start at a garden center. To take that a step further, if you save your own seeds from open-pollinated varieties you start yourself, the next generation of seeds will be free to you. It’s true that to start seeds you’ll need to spend a bit of money upfront on supplies such as seed-starting mix and grow lights. But in the long run, you’ll save big bucks by not having to purchase your transplants.

Achieve Greater Success with Regionally Adapted Seed. Not every variety of every crop will thrive in every region. When you start your own seeds, you can choose varieties that are regionally adapted to your area, leading to healthier plants and better yields. 

Give Crops a Head Start. You can start certain crops such as lettuces indoors, set out the seedlings as winter comes to a close, and then harvest heads weeks before you would have been able to if you’d direct-sown seeds in spring. (Bring a row cover into the mix, and you’ll be even further ahead of the game.) In many regions, the only way to grow certain slow-maturing crops is to give them a head start via indoor seed starting.

More Control Over Sustainability. The more self-sufficient you are in the realm of growing food, the more control you have over the sustainability of all activities involved. When it comes to seed starting, you can make a difference in several small but meaningful ways.

Consume fewer resources by reusing and recycling materials for seed pots. Use seed-starting mixes that don’t contain peat, which — even though it’s ubiquitous in the gardening world — is being harvested from bogs at an alarmingly unsustainable rate. Coconut coir made from coconut husks is a better option that retains moisture just as well. Finally, support seed companies using sustainable practices.

Nudges You to Plan Ahead. We all know that moment when life’s busyness gets away from us and we think, “Yikes — I need to start spring planting soon!” We’re thinking of compost, bed prep, seed ordering we should have done weeks ago, and on and on. If you get in the habit of starting seeds at home, you’re forced (in a good way) to think ahead, decide what you want to plant and what you’re going to start indoors, and order the seeds you need.

Goes Hand-in-Hand with Seed-Saving. If you save your own seeds — a worthy, wonderful pursuit for the self-reliant gardener — it makes sense that you would want to grow your own transplants. And, vice versa, if you’ve made the initial investment in a nice seed-starting setup, it’s that much easier and more inviting to dive into the science of seed saving.

Save Space in Your Garden. If you’re really tight on growing space, starting some crops indoors can help you take strategic advantage of every square foot of soil. For instance, let’s say you have a nice big patch of spinach you’re still harvesting from at the same time that you’re thinking of planting a couple of hills of cucumbers. Instead of choosing one or the other, start your cucumber seeds indoors. Keep harvesting from your spinach during the weeks when your cukes are growing into strong little plants indoors, and then, about the time your spinach will be thinking about going to seed anyway, you can hoe under that crop and pop in your cuke seedlings on the same day. (Choose a vining variety of cucumber and give it something to climb up to save even more space.)

Have Way More Fun at Seed Swaps. If you’ve ever been to a seed swap — or even just flipped through a lovely seed catalog — you’ve probably seen all kinds of intriguing, beautiful seeds for crops that don’t direct-sow well. Get the hang of seed starting, and you’ll never be held back again! I’m being a bit silly here, but it is truly nice to be able to swap or try seeds of all types.

10 Seed-Starting Tips

Create a Plan. One of my favorite aspects of growing my own seedlings is the wintertime planning. Just when I’m longing for days outside in the dirt, I can sketch out what I want to plant during the next growing season, read about new varieties I want to try, and create a calendar of when to start my seeds. Tomatoes, peppers (hot, bell and sweet), eggplant, broccoli, cauliflower, Brussels sprouts, kale, cabbage, basil, parsley and onions are all perfect candidates for seed starting. These crops tend to do much better if planted as transplants, and don’t direct-sow as easily.

If you have plenty of space in your seed-starting setup and/or if you have limited space in your garden, you can start lettuce, cucumbers, melons and squash, too. You’ll need to decide ahead of time what crops you’re going to start indoors and how many of each plant you want to grow (and have room for). Make a list, order seeds early, and map out a simple planting calendar.

Make Your Own Mix. Seed-starting mix needs to be a light medium that holds moisture well. There are a lot of seed-starting mixes available at garden centers, but you can save even more money by creating your own at home (plus, mixing your own allows you to ditch peat and use coir instead). If you’d like to make your own mix, try this well-balanced, coir-based recipe:

• 18 quarts vermiculite
• 12 quarts coir
• 12 quarts mature,
• disease-free compost
• 3/4 cup blood meal
• 1/2 cup limestone
• 1-2/3 cups greensand

(Note: Coir comes in dehydrated bricks from garden centers and pet stores; the measurement here refers to the moistened, expanded material.)

Use Top-Quality, Regional Seed. To ensure the strongest, healthiest plants that will grow best in your micro-climate, choose high-quality, local seed. Purchase from local seed companies whose growing methods and business practices you trust. Look for those that do their own variety trials. Also, attend and get seed at local seed swaps, talking to growers about their varieties and seed-selection practices.

Don’t Be Picky About Pots. While the grid-like seed-starting trays you’ve probably seen in stores work well, you can use all kinds of small containers to start your seeds: empty yogurt containers with a few holes punched in the bottom, seed-starting cups made out of old newspaper (plant the whole thing and the paper decomposes), and small pots you’ve saved from purchased flowers and plants. Also try making pots from eggshells, egg cartons, toilet paper rolls, or even a seed blocker, a neat contraption that allows you to stamp out a block of soil that acts as a “pot.”

Do start in individual containers (or individual seed blocks) rather than planting multiple seeds in, say, a large, shallow tub; this will ensure that you don’t disturb plants’ root systems when it’s time to transplant them. In addition to individual containers, you’ll need a shallow tray in which to place your containers and hold water. You can use darn near anything for a tray — I’ve borrowed baking dishes from the kitchen for this purpose.

Get Your Timing Right. This tip, of course, harkens back to No. 1: If you sketch out what you want to grow ahead of time, you can create a quick calendar of when you actually need to start each type of seed. In general, start tomato seeds six to eight weeks before your average last frost date, start peppers eight to 10 weeks before this date, and start most brassicas such as broccoli four to six weeks before your last frost. Start a second round of brassicas for your fall garden about 12 to 14 weeks before your first fall frost. Check seed packets for specific varieties and for other crops to see recommended times for planting seeds indoors.

Plant Two, & Use a Pencil. I always plant two seeds per container and then thin the seedlings later. If I’ve made a careful plan and I’m giving real estate in my seed-starting setup to grow, say, 10 broccoli plants, I want to be sure I actually end up with that many. So planting two seeds is insurance. When you thin seedlings, never pull the seedling completely out of soil mix. Instead, just use scissors and cut the weaker of the two seedlings at the soil surface so you don’t disturb the delicate root system of the seedling you are keeping.

When you plant your seeds, use a pencil to do so. Dump out some seeds onto a flat, dry surface, and then dip the tip of a pencil in water and touch the pencil tip to a seed. The seed will stick to the pencil, and then you can easily poke the seed into your pot of mix. Trust me — it’s like magic, and is so much easier than using your fingers for planting, especially if you’re dealing with tiny seeds.

Water Well. Be sure to keep your seed-starting mix moist as your seeds germinate and as your seedlings grow. Don’t water tiny seedlings with a watering can, as the force of the water coming out of the spout can damage the delicate plants. Instead, water by spraying seedlings well with a spray bottle or, better yet, by adding water to the bottom trays holding individual containers.

Lots of Light. You have three options when it comes to lighting up the lives of your growing plants: natural sunlight, fluorescent light bulbs and specialized “grow lights.” There are pros and cons to each. Sunlight is, of course, cheapest and least energy-intensive — but you need really strong light in a south-facing window to make it feasible. If your seedlings don’t get enough light, they’ll quickly become “leggy” (spindly and weak) as they put all their energy into reaching more light.

If you use fluorescent lights or grow lights, keep the tops of the growing plants no more than an inch away from the lights. I start my trays out propped up on several books, and then slowly take the books away to lower the trays as the plants get taller. Keep your lights on the seedlings for 14 to 18 hours daily; an inexpensive timer hooked up to your lights can help you ensure this range.

Cozy and Warm. To ensure good germination and strong plants, keeping your seeds and seedlings at a consistent, warm temperature. They shouldn’t get too cold, but they also shouldn’t get too warm — about 70 to 80 degrees is a good range. Some gardeners use an electric heat mat underneath each seed-starting tray, but I don’t think mats are worth the extra expense if there’s another easy way to keep the seedlings warm. Try placing your seed-starting setup next to a heat source, like a heater vent or radiator — and if you do start seeds in a sunny window, always place a curtain or blanket between the seedlings and the window during nighttime.

Always Harden Off. At least a week before you transplant your starts, start getting them used to their new home: the great outdoors. It’s essential to put young plants through this hardening-off period. Set plants out for a couple of hours the first day, in a protected location where they won’t experience rain or strong winds. Build up from there, letting your plants stay outside for a longer period of time each day. At first, limit the amount of time the seedlings spend in direct sun, because they can get sunburned. After they adjust to their new environment, they’ll be ready to live in the garden and provide you with delicious, healthy food.


Shelley Stonebrooklives and gardens in the Pacific Northwest, and usually starts way more tomato plants than she has room for in her garden (thankfully, starts make great gifts). Read more of Shelley’s food and gardening tips on her blog, The Rowdy Radish.

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