Starting Seeds Indoors

Starting seeds indoors can be incredibly satisfying, and it doesn’t have to be a messy process. It is incredibly important to start everything from seeds to prevent the introduction of disease and bugs into the indoor garden. If you want to read more about this important step for the biosecurity of an indoor garden, click here.

Starting plants from seeds has some additional benefits. It is a great way to get lots of rare types of fruits, flowers and vegetables, specimens you would never find as plants in a normal garden store. Seeds are MUCH cheaper than seedlings and plants. It usually doesn’t take too long to see results and the results are ALWAYS fun.  There really is nothing more satisfying than growing flowers and food from seeds.  

I have a nice portable gardening tray and I always do my seed planting right on the dining room table, often with my young (messy) boys helping me out. With the portable tray, I can bring everything I need, and it’s remarkably tidy. I have made some other adjustments to the usual seed starting process to keep it cleaner and more compact. Because I do this on my dining room table, over a rug.

Seed Starting Supplies: 

1. Container. You’ll need something to hold the soil. This can be anything, egg containers, biodegradeable paper pots, or boring old standard seedling start trays. I get lots of these free from the back section of my local large gardening store. They have trays and trays of them all summer and are often willing to give away quite a bit to those who ask. 

2. Growing medium,. I use anything that is nice and light to give the delicate roots room to spread. My favorite seed started medium is the Jiffy organic seed starter mix. But Coir mix is incredibly fun to watch expand as it gets reconstituted with warm water, and works well to boot. You can also use any light garden soil.  Most people wet the soil before doing the seeding, but I find that is a much messier situation. Instead, I keep mine dry and just make sure the soil is packed in by swirling my seed label or labeling pencil through the soil filled cell to make sure there isn’t a large air pocket in the cell and that the soil has settled. I am also careful not to fill the cells too high. I stop about 1/4″below the edge.  This makes for a much tidier experience. 

3. Seeds. Obviously you’ll need these. There are many online seed companies for the harder to find varieties, and some of my favorites are Johhny’s Selected Seed company, Renee’s Garden Seeds and Baker Creek Heirloom Seeds. The best thing is that on these websites you can still get seeds in January when no one else is gardening. For more common varieties, or when it’s actually gardening season, the big garden stores and even grocery stores have the more common varieties. The seeds are cheap but the germination rates can be a little lower, as the seeds are often older. But, we once even got a pumpkin seed to grow after it had been roasted  from my son’s pumpkin seed cooking experiment at pre-school.  So, maybe it’s worth trying to stick anything in the soil and get it to grow! I always try “container varieties”, they usually won’t get as big and and are “high producers”.  That’s obviously a plus in a small space! Occasionally, seeds need extra work. Some seeds need to be placed in the freezer for a week before they’ll sprout, others need to be soaked in a wet paper towel for a day or two. Usually, you can just plop seeds in the seed starter soil, but it’s always a good idea to read your seed package for any special planting instructions so you don’t miss something obvious that would increase your germination rate. 

4. Seed labels. Popsicle sticks, plastic or bamboo wooden seed labels, anything will do as long as it won’t dissolve in water. Just don’t forget this step or you will have no idea what you’ve planted! I like to write down the full seed name, variety, brand, and date of planting for future notes and comparisons. That way if something is super tasty or is a great producer, I know exactly what it was.  In addition, if I know when I planted those carrots, I won’t accidentally pull them out a month early only to find they are green, hard and small! It is so hard to wait sometimes. It helps a lot to have a date in mind for harvest.

5. Vermiculite. I got this tip from Floret Farms. I spread this on top of all of my seeds to help lessen the chance for mold to take hold and “damp off” the tray. This step is even more important for teeny tiny seeds. Instead of burying them in soil, a fine layer of vermiculite is all they need to cover them. 

6. Seed starter mats. These mats use very little energy and warm the little trays so the seeds sprout much faster.  They can speed up the germination process by as much as 3-4 days. They are not a requirement and people often will just place the seeds on top of the fridge.  But if you have a special lighted place, the seed mats fit perfectly under and do the job to perfection. 

7. Water. Once your seeds are planted and vermiculited, it’s time to water them! It’s best to water from below, that way the seeds don’t dislodge. It is also MUCH CLEANER to do it this way. Basically I walk my seed trays over to where they will be sprouting, and THEN water them from below. If you water and then move them, you will have a puddle on the floor every time. Try to keep your seeds always moist but never wet. The one thing that will surely kill your little budding experiments is letting them dry out.  The first time I water them, I give them about a solid inch of water and let them soak it up. I check on the soil about an hour or so later and make sure that the tops of the cells are moist.  If they aren’t, I just push the soil down a bit to make sure there are no air pockets.  After this hour, I pour the remaining water off the tray if I think of doing it. Most gardeners would be horrified to learn that I leave my seedlings in standing water about 4 days a week but I live in Colorado where it is so dry that we can do this without worry of mold!!

8. Light. A lot of seeds don’t actually require light to germinate, but once they have sprouted, they all need lots of light, very close to the actual plants.  If the light is too dim or too far, the seedlings will be very skinny and long. Often, a south facing window sill in summer can provide enough light, but if not, the plants will become skinny and too tall. These “leggy” plants won’t transplant well and make for weaker plants in general. So, I strongly suggest that you supplement with LED lights. Since LED lights don’t generate a lot of heat, they can be very close to your seedlings without burning them. Leave the lights on your seedlings for approximately 16 hours a day.  It is recommended to have the lights be just one inch above the plants and then move the lights up as the plants get taller.  That is a lot of work and constant adjustment. I am always starting seeds indoors, and since I always have a few trays of seedlings growing I would have to spend all my free time moving the lights up and down. Additionally, my trays are never all one crop so my mismatched seedling heights are very difficult to light properly with weak lights. My solution – I have one very bright grow light at a fixed point over the seedlings. This is the only light in my garden that is specifically a grow light. And it is certainly the most expensive light in my garden. But this one splurge has saved me hours of labor and headaches. It is the Black Magic 45 W LED grow light, and it is awesome. (Update, I just noticed that grow light is sold out on amazon currently, but this one is very similar.) It hangs about 6-7 inches above the seedlings and gives them a very good start. Once the plants grow past the lights, that’s my signal I had better plant them in the garden. 

9. Humidity dome – This is another one that isn’t essential but can help. Ziploc bags or suran wrap laid across the seeds works just as well. Just remember to remove as soon as the seeds  actually sprout. I have gotten away from using these since I find that it just causes everything to mold a bit.  But that’s probably only because “I leave my seedlings in standing water about 4 days a week”.  See point 7.  Maybe I’m embarrassed now

Seed Starting Supplies:
Growing medium
Heat Mat
Planting Trays
Humidity Dome
Planting Labels

Seed Starting Indoors

Here is the whole, tidy process with pictures!

1. Fill the tray (or egg carton, or degradeable pots) with the fine seedling medium.  Most people wet the soil at this point but I think it’s cleaner and easier dry. For added tidiness, don’t fill the trays too high.

How high to fill the trays.

2. Place your selected seeds in the pots.  The general rule is to plant it as  2-3 x as deep as the seed is wide. So a squash seed like this should be planted approximately an inch deep, but a tiny seed like lettuce should be only covered lightly with soil or vermiculite.

Plant your seeds

3. I like to use the seed label to just twirl the soil around to make sure there are no air pockets in the soil and get the seed planted at the level I like it. You can also use your pencil for this but then your pencil gets dirty.

get them to the right depth with a simple twirl of the plant label

4. Don’t forget to label it! I like to include the variety, sometimes the brand, and the date of planting.

don't forget to label

5. Lightly spread vermiculite over the top of the planted seeds. 

Spread vermiculite lightly on top

6. Walk your tray over to it’s nestling spot and THEN water from below so you don’t wash away the seeds and all your hard work! The soil will wick the water up to the seeds. This long-spouted watering can is perfect for the job.

water from below

7. Place the seeds on a warm place such as a heating mat, the top of a fridge, or on a sunny window and cover with a dome if you choose. I find that adding the dome doesn’t do much except trap too much humidity and cause fungus to thrive so I choose not to use it. 

And then check back in a few days to see some action!! Here are those same trays just 3 days later…

now you've started seeds indoors

Now you are ready to start your own seeds indoors, whether it’s for an indoor or an outdoor garden!

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