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HOW TO: Start Seeds Indoors

Updated: Mar 9, 2022

The first day it hits above forty degrees February an alarm goes off in my brain: "SPRING IS HERE! TIME TO GARDEN!" it screams. But if you're like me and live in WNY, you remember that spring is absolutely NOT here and won't be for a long time. I have two choices: fall into a deep depression, or scratch that gardening itch by starting seeds indoors. If you've never started seeds before, don't be just need a plan and the right equipment to get a head start on summer. Let's go!

The Benefits of Starting Seeds

Save money.

A pack of six tomato seedlings sold at the local nursery costs around $3. A packet of thirty seeds costs between $2 and $5. Pretty easy math right there.


Starting seeds indoors can be a great way to try new varieties of vegetables and flowers that you might not be able to find at your local greenhouse. Want jalapeno peppers that have the flavor without the heat? Purple-skinned carrots with red cores? Palm sized butternut squash? All that and more. There's an entire section of seeds that grow smaller varieties of veggies if you have limited space and/or garden in containers. The seed stands at Home Depot represent a fraction of the amazing varieties available to home gardeners.

Environmental tolerance.

America is a big place with a huge range of macro and microclimates. Certain plants that thrive in Georgia may not work here, and vice versa. Unfortunately the bulb and seed stands set up big box stores don't always contain options that are suitable for our climate. It drives me nuts when I walk into Home Depot and see "perennial" ranunculus bulbs for sale. Are they perennial?


If you live in Zones 8-10, yes. But we live in Zone 5/6 and the bulbs will not survive the deep freezes we get in the winter. Unless you're planting them in pots and moving them into a protected space to overwinter, you might as well throw your money straight into t

he trash. It's not necessarily Home Depot's fault- the person that's doing the ordering also has to order washing machines and miter saws.

On the flip side, seed companies are focused on cultivating seed stock. Seeds fall under a number of headings: heirloom, organic, disease-resistance hybrids, container and small space varieties, seeds for commercial growers, and so on. They also make recommendations based on your climate. Take the humble cantaloupe for instance. Anyone that's tasted a locally grown, in-season melon can tell the difference between that and the pale orange tasteless bowling balls sold at the grocery store. Unfortunately these delicious fruits require a very long growing season of consistently hot temperatures, so I'm trying a variety that was bred to thrive in our short, cooler summers.


There are a few. The cost of purchasing the equipment is probably the biggest barrier to entry. But life is about the journey, not the destination. Plus, the most expensive purchases (grow lights and heat mats) are reusable. If after your first go-around you decide starting seeds indoors is more trouble than it's worth, there are at least fifty gardening enthusiasts (including myself) that would happily buy your used supplies off of Facebook Marketplace or Craigslist.

Seed Starting Supplies

You can't grow healthy seedings without the right supplies. All of the following can be found in most big box hardware stores and of course, Amazon. If you want to look for premium quality materials check out the online catalogues of Gardener's Supply Company or Johnny's Selected Seeds.


This is the place most people go wrong when starting seeds for the first time. When I first started I tried placing the seeds in multiple locations- sunny windowsills, under incandescent lights, even under the fluorescent lights in the basement. The seeds grew, but they they were leggy, pale, and withered away the instant I moved them outside in the spring.

The problem? Not enough of the right kind of light. Seedlings need 14-16 hours

of full-spectrum light to grow. Few houses get the amount of natural light seeds need; even a southern facing windowsill only gets a half day of direct sunlight. Fluorescent lights don't cover the range of the light spectrum plants need, and the heat from incandescent lights can fry your seedlings if you aren't careful.

What to do? I recommend purchasing LED grow lights to make sure your light needs are met. These produce very little heat, are relatively inexpensive (think $30ish), and offer the full spectrum of light your plants need to get off to great start. I can be forgetful so I use an outlet timer to turn the lights on and off, but this is totally optional. Hang the lights about four inches above your seed trays and continue to move the lights up as the plants grow. If you purchase nothing else from my list, purchase a grow light.


Most seeds need the soil to be at least 65 degrees to germinate, so If you plan on starting them in a space that's cooler than that (basement floor, garage, etc.), you'll need to purchase a heat mat. Be sure to purchase one made specifically for plants- they are waterproof and keep the steady temperature that the seeds need for germination.


I like to use the seed starting trays that are commonly found in big box stores. The brand doesn't really matter, they all have the same three components: a base tray to hold water, a seed tray with cells to fill with soil and seeds, and a clear cover that creates a mini-greenhouse effect. I like that these keep the water contained and the seedlings protected until they're ready to be transplanted to larger containers. They aren't expensive and I reuse them every year.

If you are interested in recycling other household materials, options can include peat pots, egg cartons, recycled plastic containers from the annuals you bought last year, plastic tubs, Dixie cups...the list goes on. Just be sure whatever you use has a way to drain water so that the seedlings won't drown. You'll also want to have some type of basin to catch the access water in (unless you're growing in an area that you don't mind getting wet). Dixie cups, peat pots, etc. can be placed in plastic bins or on the lids to plastic totes. Even a tarp will help keep the access water contained.

"Soil" Make sure you purchase sterile, soilless potting mix for starting seeds. Bags are usually around $6 and located by the seed starting supplies at stores like Home Depot or Lowes. Terms like "sterile" and "soilless" may sound like the opposite of what plants need to grow, but the opposite is true. Regular garden and potting soil is teaming with life...good things (like minerals, beneficial bacteria, and organic matter), and potentially bad things (like harmful fungi and diseases). Young seedlings are particularly vulnerable to environmental stressors, so it's important to start with a mix that is as safe as possible. Will regular soil work? Of course. But the warm, moist environment you've created for your seedlings can also encourage the growth of other things that can lead to problems down the road.

SEEDS! My favorite part. I strongly recommend checking out varieties sold by reputable seed companies. I personally order from Johnny's, Seed Savers Exchange, and Fruition Seeds because of their high quality product. Not only do they sell a wide variety of seed, but they provide a wealth of information on how to create and grow healthy, happy plants. Look for companies that are located in similar climates as ours. Fruition Seeds is located in the Finger Lakes region, and offers varieties that do well in our climate.

If you choose to go this route, look for varieties that highlight the taste, disease resistance, and ease of growth. Seed varieties that feature "packability" or "crop uniformity" are geared towards commercial growers and these attributes often come at the expense of taste.

You're welcome to check out the selection on the stands in the hardware stores: they're definitely cheaper than the catalogues, but you will be limited when it comes to variety. I've seen certain seeds for sale that are completely unsuitable for our climate. It's also very possible these seeds spent time baking in the back of a store room or box truck prior to being put on the floor. If anything, purchase seeds from a locally owned nursery. They are hopefully featuring varieties that thrive in our area.


This may seem like a no-brainer but it's worth mentioning. Once your seedlings start to grow eventually many will have to be transplanted to larger pots. So before filling the entire 72-cell starting tray ask yourself: do I have enough room for 72 plants? Do I even need 72 plants?! Let reality be your guide.

Seed starting can be messy so make sure you place your trays in a place that is easy to clean. If you're a messy waterer like me be sure to choose a spot that can handle some moisture. I do all my growing in the basement by the sump pump just in case things get really out of control.

What to Grow

Before ordering your seeds you need to get a garden plan ready so you have a realistic idea of how much space you're working with. Most of the vegetable plants in our area are started indoors during March and April, so make sure you order your seeds before then. Some varieties run out quickly so the sooner you order the better.

Each packet comes with instructions on how to plant and how long they'll need to grow before being moved outdoors. You'll see the term "average last frost date", which refers to the day in the spring where you expect the last frost. The majority of vegetable crops will not survive a frost so be very careful not to plant things out too early. I always wait until after Memorial Day weekend (although I am tempted to plant weeks in advance of that date). Better safe than sorry! I use the Old Farmer's Almanac website to determine my ALFD, just plug in your zip code and it will give you a date. You can also contact your local Master Gardener Cooperative extension and get a date from them too.

While some plants benefit from an early start, others prefer to be planted directly into your garden (aka "direct sown"). Each seed packet while indicate which start method is preferred.

Plants you should start indoors: tomatoes, peppers, eggplant, celery, broccoli, head lettuce, celery, onions, leeks, winter and summer squash

Direct sown crops: leaf lettuce, garlic, cucumbers, strawberries, dill, cilantro, peas, beans, corn, bulb crops (carrots, radish, beets, parsnips, turnips), spinach, arugula

Each plant family has different needs, so be sure to follow the instructions on the seed packet. If the seed packet is vague, visit Johnny's Selected Seed website to find growing guides.

After Starting Your Seeds

Here are a few things to keep track of after your seeds are planted and settled in.


Make sure you keep the soil evenly moist. If using heat mat, make sure you're checking the water levels daily. Once a seedling withers from lack of water there's no coming back. On the flipside, you don't want your seedlings sitting in a pool of water. Yellowing leaves and stems may indicate overwatering, weakening the overall health of the plant.

The second year I tried starting plants indoors I started my tomatoes about 8 weeks to early and seriously overwatered them. I ended up with a bunch of 18 inch tall yellow, pathetic plants that looked even worse when I brought them outdoors. I have a tough time giving up on plants so I decided to plant them anyways (hey, I cant always pick up more at the nursery if these bite the dust!) Believe it or not, they did surprisingly well. I lost about 25% but the remaining plants turned into normal looking tomatoes. It's amazing what plants can do.

If you use the trays I recommended, you can pour water directly into the base layer. The stream from a watering can or hose would be way too powerful and could potentially end up killing your baby seedlings, so I recommend getting a mister or spray bottle to water your seeds from above.


All the warm air and moisture encourages your seedlings to grow...and other diseases as well! If you're using the sterile soilless mix I recommended you shouldn't see too many problems, but I've had issues with mildew in the past (the plants look like they got dipped in flour). For this reason, I like to keep a small table fan running over the plants to encourage air circulation. Just keep in mind you may have to water more often.


If your plants get large enough that the roots are growing out of the drainage holes at the base of the container, it's time to replant. You can stick with the soilless mix or switch to potting or garden soil. Peat pots are a good choice because they can be placed right in the ground when it comes time to move your plants to the garden. I like to save all the plastic pots I get from the annuals I buy at the nursery and transplant into those. Whatever you choose, make sure the container has good drainage and is an appropriate size for your plant.


The process of "hardening-off" refers to getting your plants tough enough to handle the outdoors. Your seedlings have existed in a windless, pest-free setting of constant ideal temperatures. Plus, they've been sitting under lights that, while providing the necessary spectrum for growth, do NOT match the intensity of direct sunlight. In other words, they have book-smarts but not street-smarts. Gardeners harden off their plants as a way to gradually adapt their seedlings to this major change in growing conditions.

The process is fairly simple. Start by placing your seedlings outdoors in the shade daily, two weeks prior to their transplanting date. Begin with the leaving the seedlings outdoors for twenty minutes the first day, and gradually increase the outdoor time by 5-10 mins during the remaining weeks. In the last few days of this process, try placing them in dappled shade or sunlight.

Is this a giant pain in the ass? YES. Especially if you're like me and have to walk 300 plants up and down your basement stairs everyday. But I must begrudgingly inform you that it's a necessary part of the process. I've tried every way around this, including not hardening-off at all, or only hardening-off a few days before transplanting. Both methods killed or seriously injured my plants. One year I left them out for two hours in the shade the first day, which killed them pretty much instantly. So just do it folks, because the only thing worse than carrying these plants in and outside every day is watching your months of hard work whither away in the sun.


Once you get a your first season of seed starting under your belt this will all seem less intimidating. All you need is a good plan and the right tools are all you need to get a head start on summer. Happy planting!

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