Cover Photo by Markus Spiske from Pexels
It seems like just yesterday we were all clearing the garden and prepping for the long, cold winter. Luckily, most of us didn’t have to deal with frigid temperatures and mountains of snow, but the seeming lack of a real winter may have caught a number of gardeners off guard.
Boom… here it is. Seed starting time already.
Some of us use the depths of winter to leaf through seed catalogs, longing for the day when the birds begin to chirp and the grass turns green. In the absence of this mental cue, many of us may be caught in a scramble to gather everything we need (or think we need) to get those early starts going.
No sweat. We’ve put together the top 10 things every gardener needs to embark on their seed starting adventure, all wrapped up in a neat little blog post. Look through the list seed starting supplies, find out what you need, and go get started.
The 10 Seed Starting Essentials

Trays or Flats
This one is sort of confusing, because what most people would consider a seed tray or a “flat” is actually two things. First is the tray itself. This is usually a standard 1020 tray (1020 just means 10″ x 20″). This is just a flat, open tray without cells and with or without holes in the bottom depending on your preference. With holes allows for drainage, without holes will not.
The other is the lightweight insert which we’ll cover next. There are also proper propagation trays – beter known as prop trays – that feature many different cell configurations but are a single unified piece. Once the plants are ready, the “plugs” are just pulled out and put in place. These are designed more for larger growers with special equipment that allows for very quick transplanting, but work just as well for small growers too.
Protip: Many people use no hole trays in conjunction with the celled trays below (which have holes) as a self-watering seed tray system. This works great for plant propagation and seed starting.
Inserts
The other component of a seed starting tray is the insert, and as the name implies, this is inserted into the 1020 tray. An insert is typically thin grade plastic and has multiple cells in one sheet – up to 72 depending on the orientation – and can also usually be broken apart into smaller “cell packs.” It can’t be carried on it’s own because it’s so flimsy, which is why you need both. Our most popular sizes are 606 and 806 inserts. The former has 6 cell packs of 6 cells for 36 total cells, and the latter has 8 cell packs of 6 cells for 48 cells. This makes for very efficient seed starting since you can place one or two seeds in a cell, and when the seed germinates you can pop out the “plug” and plant it.
Propagation Mat
If you’re going to be seed starting before Mother Nature would otherwise allow them to grow, you’re going to need to use the same trigger she does to tell your seeds its time to grow. That trigger is heat. Specifically, soil heat, or more accurately, soil temperature. In order for seeds to germinate, the soil needs to maintain the proper temperature. In the early spring it’s usually still too cold for this, but we can trick our seeds by using a propagation mat. A propagation, or heat, mat (also known as a seedling heat mat) is placed under your seed tray and keeps your soil nice and toasty around the clock, which leads to higher germination rates in less time. Seeds like the same temperatures that you do – between about 60 and 80°F – and that’s the exact range a seedling heat mat is great at maintaining. I’ve had seeds sprout in as little as 1 day using a heat mat.
Grow Lights
Most of the time if you are seed starting early, you will be starting them indoors. I start mine in my basement, and others may start in the garage or other such places. The key here is that these places don’t have a lot of light, and light is one things that seedlings are absolutely going to need. That’s why it’s best to get a florescent grow light system of some sort to provide essential light to your fledgling plants. You can either get a system, complete with integrated stand, or a stand-alone fixture you can hang yourself. ***Protip: Keep the lights about 1-3″ inches from the highest leaves of your plants to prevent stretching from light starvation.
Seeds
It goes without saying that you will need seeds, and we certainly do offer seeds. However, it’s not really our specialty and there are tons of places out there that have great selection of many different types of seeds. I always prefer heirloom varieties because then you can save seed from year to year if you follow certain guidelines for the specific plant you’re working with. However, for ease of use and production, hybrids usually can’t be beat. It’s your preference whether you look for non-GMO or organic labeling, but as a general rule, anything heirloom will be non-GMO anyway.
I’ve used Johnny Seed, Park Seed, Baker Creek Seeds, and Seed Saver’s Exchange and highly recommend all of them. For medicinal herbs, some rare and hard to come by, try Strictly Medicinal Seeds.
Soil or Medium
You’d think that soil was an easy one. Just walk outside and scoop some into the cells of your insert and you’re all set, right? Well, first of all not everyone has the luxury of having good soil, and secondly, just because your seeds will grow in your native soil doesn’t mean you have to or even should use it for seed starting. It’s good to use a sterile, soiless, peat based growing medium. This way, you know there are no nasties lurking in the soil plotting to destroy your plants. Fill your inserts with the growing medium, place your seeds, and cover with a little compost if you have it.
Soil Sieve
A sieve isn’t essential, but it will make your life a little easier. It’s already easy enough to fill your insert with growing medium, burrow a hole for you seed, drop it in, and cover it up. What the sieve will allow you to do is place all your seeds, and then shake a fine layer of medium or compost over the top of the seeds. This way, the amount of soil on top of your seeds is uniform and not too tightly packed, which could prevent your seed from breaking through.
Transfer Pots
Transfer pots come in a lot of shapes and sizes, and depend on what you’re growing and how long it will be before you plant in the ground. Basically, when your seedlings get too big for your seed tray, they need to be moved to bigger pots. This way, the roots have more room to stretch and the plant can remain healthy until it’s time to go outside. The most popular transfer pots are between 3-5″ square pots, and usually the associated carrying trays.
Row Cover
Spring planting is always a gamble, and more often than not we gardeners are going to jump the gun. That’s probably especially true this year.Inevitably, Mother Nature will throw one last frost at us after we have taken the plunge and put plants in the ground. These early spring cold temperatures can spell disaster for your young plants. That’s where frost protection fabrics come in. They are simply a light and water permeable plastic fabric that you can drape over your plants that will keep them just warm enough on frosty nights to stave off freezing.
Frost fabric also comes in handy when you are direct sowing seeds to your garden early in the season. Seeds need a specific temperature to germinate, and you shouldn’t be planting any warm loving plants too early, but there are plenty of plants that don’t mind the cool weather. Spinach, lettuce, kale, radishes, beets, and many more will germinate as low as 50 degree soil temperature. However, they do better with a little more warmth. If you’re planting early, just lay some frost fabric over them until they germinate and then proceed as normal. Our experience shows you can achieve germination as much as a week faster using this method.
Composter
Compost is the best thing you can do for your soil, and everyone can benefit from using it. Keep in mind, if you want happy plants, then you need happy soil. And compost makes any soil very, very happy. There are plenty of small compost bins designed if space is at a premium or you won’t need much compost, but there are also plans out there to build your own larger compost bin. Decide what’s right for you and start composting now.
Bonus Seed Starting Tip #1: Soil Test Kit
A test kit won’t necessarily help your seed starting or plant propagation efforts, but it will help you ensure your seeds flourish once transplanted to the ground outside. A soil kit will tell you if you soil is deficient in any specific nutrients, if there is something present that’s harmful, and how healthy your soil is. This is critical information, because if your soil is lacking, your plants will be too.
Bonus Bonus Seed Starting Tip #2: Fertilizer
If you want to make sure your plants get off to a good start, give them a boost with some appropriate fertilizer. Be careful though! In the seedling stage, plants are very vulnerable to nitrogen burning so use a mild, preferably organic, fertilizer. Use it sparingly and your plants will thank you.
Conclusion
There you have it, the best seed starting supplies to get you going this spring. What did you think of our recommendations? Did we miss something? Let us know in the comments below.
How much water in the trays?
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I like to fill them up about half way. The first time you fill the soil will suck up all the moisture pretty quickly, but after that you should only have to top off the water every couple of days. It’s good to let the water run out, so the roots are sitting in water, but that also runs a high risk of letting the soil dry to much and killing your plants. Your usage will depend on how frequently you’re able to check on your plants.
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