This post contains affiliate links see my full disclaimer to learn more. Want your garden to be the envy of the neighborhood this year, without blowing the bank? Try these Tips and Tricks for Starting Seeds Indoors and you will have an enviable garden in no time.
Starting your own seeds is an effective and affordable way to get a jump on the gardening season. Starting seeds indoors allows you to create a full gorgeous and totally custom garden, while everyone else is still waiting for the garden centers to open.
So that being said, now is the time to start thinking about indoor seed starting. If you haven’t started already, here are some key tips to get you off to the right start.
First, there are a number of things to consider when starting your own seeds, such as what are the advantages to starting your own seeds, what tools you will need to have on hand, what soil mix to use, how and how often to water your seedlings, unique seedling planting requirements and germination rates, whether to use grow lights or not and when to pot your seedlings up and when to plant them out.
We will be tackling all of this below, so hold on to your gardening gloves because we have a ton of stuff to cover!
Why start your own seeds?
Starting seeds indoors is a great way to get a jump on the gardening season, especially in colder climates. Indoor seeds usually have better germination than seed that are direct seeded in the garden and indoor seeds are older and usually bigger than seed started outdoors.
Seed starting is cost effective, a single packet of 10-20 seeds is roughly the same cost as one single nursery plant bought from the garden center. So, it makes sense to start your own seeds.
You can have more control over the growing conditions indoors vs. outdoors, which leads to better germination, which also saves you money; seeds that don’t sprout are money wasted. So, although seed starting materials might cost a bit of money, you save huge in the long run.
Hopefully, I’ve got you convinced why to start your own seeds, now here is what you need.
Tools and equipment for Starting Seeds Indoors
I recommend using clean/sterile seed starting trays and plastic seedling cells which can be purchased for any nursery in late February or March. I try to avoid using plastic in my life as much as possible but, plastic seed starting trays are easy to find, easy to clean and easy to store. So to reduce my consumption I try to take good care of my plastic trays, I wash and store them each fall so they are ready for use in the spring.
It is really important to always use clean cells and trays before starting seeds, doing so helps to prevent soil born pathogens that can cause real harm to your seedlings. There is nothing worse than nurturing a little seedling along for weeks, only to have it die from some soil born disease.
Wooden trays and soil blockers are a much more sustainable option, I just haven’t gotten there yet.
Clear plastic domes are great for keeping your seedling and soil moist, they also help keep them sterile. Soil fungus gnats are common in garden stores and can easily come home with you in potting soil or purchased plants. Once you have them, they are tough to get rid of and they can really damage your seedlings as well as your houseplants.
Indoor Seedling Soil Mix
It’s best to use sterile seedling mixture to prevent pathogens such as dampening off, seedling mix is also lofty and easy for seedlings to grow in. Here is a quick look at my custom blend seedling mix. For the full recipe see my Best DIY Seed Starting Mix article here.
Indoor Seed Starting Mix recipe:
10% Vermicompost or worm compost (high nutrient & high biology) *this is the Secret Ingredient*
For full recipe and measurements see my Best DIY Seed Starting Mix article here.
Use Care when Watering your Seeds and Seedlings
I recommend a spray mister for watering, seedlings are tender and need a gentle hand. A mister will ensure your seedlings don’t get washed away or damaged during watering. Mist your seedlings every day or two to keep them moist but not soggy – soggy soil breeds fungal diseases.
Germination Rates and Requirements
The germination rate is the length of time it takes for a seedling to sprout, germination requirements are the special conditions a seed need to sprout. Seeds have varying germination times depending on the growing conditions you provide.
Generally, tomatoes take anywhere from 7-21 days, but I have had them sprout in as little as 4 days with warm soil and my DIY seedling mix. Lettuce generally takes 4-6 days to germinate. Salvia can take as little as 48 hours when started indoors. It’s a good idea to check your seed germination rates and requirements to get the best results.
Certain seeds do better with a little pretreating before planting. For example, Lavender seeds germinate better if they have been put in the freezer for 7-10 days first, this simulates a cold season and tells the seeds its spring and thus time to get growing.
Lupin is notoriously tough to germinate but I have great success with a technique called scarification. Simply break the seed coating by gently scratching the outer shell with a fine grit sandpaper, just enough to break the outer coating without damaging the seed inside, then plant as usual.
Beans & Peas germinate much better when they have been coated with a bacterial legume inoculant. It sounds technical, but inoculant can be purchased online or at most garden stores. Mix the powder inoculant with a small amount of water to make a saucy paste, coat your beans and peas just before planting for better germination.
Peppers require warm soil to germinate, I use a seedling heat mat to keep the soil warm day and night. You can remove the heat mat after the seedlings have grown their second set of true leaves.
Seeds have an expiration date. To test the viability of older seeds, place a few seeds in moist paper towel, slip into a plastic bag after a few days. Every few days gently peek inside the paper towel to check for sprouting seeds. Plant the sprouted seeds out in soil under your lights.
Seeds also each have unique soil depth requirements, follow the instructions on your seed packet, but a good rule of thumb is to plant your seeds 3 times the thickness of the seed. Onion and chive seeds need very little soil, about 1/4 inch, whereas beans and peas like more soil and can be planted up to 1 inch deep.
When is the Best Time to Start Seeds Indoors?
Planning ahead and taking germination rates into account will help you get your seedlings out on time. You don’t want to have a backlog of lettuce seedlings taking up room under you lights if you need for starting tomatoes. Most seeds can be started indoor 4-6 weeks before your last frost day. So get you the calendar and count backwards 4-6 weeks from your average last frost date and start your seedlings during that time.
Use Grow Lights when Starting Seeds Indoors
Speaking of light when starting seeds indoors, I’m sorry to say this but a sunny window won’t cut it. Of course, there are always exceptions but for the most part it’s worth it to invest in some lights. You can spend big bucks on grow lights, but there are some more affordable options as well, it all depends on your scope.
If you are starting micro-greens on your counter, a simple grow bulb and a cute lamp might be all you need, learn more about growing micro-greens from my friend Mary Jane at Home for the Harvest. If you have a big family and an even bigger garden then you might want to get serious with some LED grow lights.
For my urban homestead I use a set of fluorescent shop lights, they are 10 inches wide by 48 inches long and hold two 15 watt T8 fluorescent bulbs. Shop lights can be sourced at big-box hardware stores or ordered from a locally owned shop. Be sure to get ones that are plug-in ready and not hardwired, or you will be calling an electrician to wire them to a light switch… not ideal.
While T8’s are not full-spectrum bulbs, they are fine for seed starting. Full-spectrum is only necessary to encourage plants to flower and fruit, not for starting seeds – so no worries.
Keep your lights on for 8-10 hours to avoid spindly seedlings. Also, keep your seedling close to the lights, if you can’t lower your lights on a chain then boost the seedlings up. Try to keep them within 12 inches of the lights and rotate the tray if the seedlings begin to lean toward the light.
Pot up, leafy and fruiting seedlings when the true leaves begin to overlap each other and the seedlings are competing with each other for light. If you are growing onions or other non-leafy seedlings, transplant or pot up when you see signs of small, healthy, white roots pushing out through the drainage holes in the plastic seedling cell.
When potting your seedlings up be gentle and work slowly, your seedlings are still tender and need some TLC at this point. Transfer your seedlings to 4-inch pots when they are ready to be hardened off. For more info on Early Season Gardening read my article here: Early Season Gardening: How to Get Growing Now!
I hope this will give you more confidence and a few new tricks for starting your own seeds indoors.
I also hope to expand on this article in the future so stay tuned for more detail and a section on how to harden off your seedlings.
Thanks for hanging out!