Welcome to the Seed Starting Series – Part 1: Preparation. I’m so excited to share this with you. This post is packed full of great information about how you can prepare to start seeds indoors. Upcoming posts in this series will cover How to Plant Seeds & Care for Seedlings, and How to Transplant Seedlings & Direct Sow Seeds in the garden. Keep an eye out for those informative articles.
Why Start from Seeds?
Starting plants from seeds can seem like an intimidating task, but really, it’s not difficult and there are some great benefits to starting plants from seeds. There are two ways to start seeds; indoors and direct sown into the garden. This post talks about how to prepare to start seeds indoors. Direct sowing will be the subject of a future article.
One benefit is cost effectiveness. Packets of 25 – 100 seeds can be purchased for $2 – $5 USD. That means the potential of up to 100 plants for a very low cost. On the other hand, if you buy a started plant in a 2” – 3” pot, you could spend between $3 – $6 for a single plant. Starting from seeds is a huge money saver, especially if you plan to grow a large garden.
Also, seeds last a long time, unlike a started plant which is a ‘one and done’ situation. Unless you plan to save the seeds from that plant. I will have an article about seed saving in the future. Don’t throw out seeds! Typically the date on the packet of seeds is the date is was packed, not an expiration date.
Of course, if you are doing a small garden or are just starting out, buying started plants is a wonderful option. There are some plants that are a bit harder to start from seeds and it would make sense to always buy the starts. In my garden I will have a combination of seedlings I started, and some plant starts that I purchase.
Another great reason to start from seeds is that it is a great way to extend the growing season and start plants several times throughout the season for a continuous harvest.
Decide What You Want to Grow
Sometimes this is the most challenging part of gardening, mostly because there is so much to choose from. So where do you start?
If you are growing vegetables for the first time, start with things that are familiar, things you would normally eat and that are appealing to you. That being said, don’t be afraid to try something new, even if it’s different variety of something you know you like, an unusual tomato for example. Part of the charm of having your own garden is that you have the opportunity to try things you can’t find at the grocery.
A word of caution; don’t overwhelm yourself by starting too many varieties if it is your first time. Be very realistic about how much you will be able to care for, not only as seedlings but in the garden as well.
Here is a list of easy crops to start from seeds indoors:
- Tomatoes
- Peppers
- Lettuce
- Kale
- Swiss chard
- Parsley
- Thyme
- Basil
- Nasturtium
- Marigolds
- Zinnia
Read 6 Steps for Planning a Garden
When deciding what seeds to start it is important to know what conditions will give seeds the best chance to germinate. Germinate means the seed comes out of dormancy and starts to put out shoots (the stem) and roots.
Starting seeds indoors extends the growing season giving the plants a head start before the last frost date of the season.
It’s important to know how long a plant takes to reach maturity. This is a factor in determining whether you start seeds indoors. Your growing season has a direct correlation with maturation periods. We’ll discuss growing seasons later in this article.
Seeds can be started indoors for plants that have a long maturation period, like peppers and some tomato varieties, particularly if their days to maturity are longer than your growing season.
Doing a quick internet search about the varieties you’re growing will provide this information. It’s also a good idea to read the seed packets and online descriptions when purchasing from seed distributer.
When looking at the details of the plants you want, note also their hardiness. Some are heat tolerant, some are frost tolerant. Consider the weather in your region at the height of summer. Be sure to choose varieties that can tolerate the climate where you live.
Many cold hardy varieties can be started indoors and transplanted before the last frost. These varieties include some salad greens, brassicas (things like broccoli, cabbage and kale), and some flowers.
Heat loving varieties that are started indoors should be transplanted outdoors only after the threat of frost has passed. Schedule your seed starting dates with this in mind.
A Note About Zones and Growing Seasons
As mentioned before, an important factor when choosing the varieties of plants you’ll grow is the number of days until maturity and your region’s average growing season. This often gets confused with growing zones.
Zones are determined only by the average lowest temperature of that region. Which is important if you are interested in year-round growing but is different than the growing season which is the number of days between the last frost and first frost of the season.
Determining the length of a growing season is fairly easy with a couple of internet searches. You need to know the average last frost date and first frost date for your region. A good place to look for this is Almanac.com. Enter your zip code (US) to generate a result of frost dates in your area.
The last frost date will be the beginning of your growing season and the first frost date will be the end. Almanac.com should automatically show you how many days are between those dates. If not, you can type “How many days between (last frost) and (first frost)” in a search engine.
For example: In my zip code, the average last frost is May 4, and first frost date is October 5 for a growing season of 153 days.
Why is this relevant?
Looking at a seed packet or plant tag, you’ll see that it mentions the number of days to maturity. For example: Lettuce can have a maturation period from 45-55 days, whereas peppers can take up to 150 days to mature depending on variety.
If your growing season is 90 days, you may consider starting seeds indoors well ahead of your last frost date for plants that have longer maturation periods. There are varieties with longer growing times that can handle some cold weather and will be fine if left out past your first frost date, though they may need a bit of protection like a frost cloth or a sheet if the temperatures dip very low.
Where & When to Buy Seeds
It can sometimes be difficult to find all the varieties you want to grow in the height of seed purchasing season, which tends to be late Winter into early Spring. I know this from experience and hearing from other gardeners. This is particularly true if you are shopping for popular varieties.
It’s a good idea to do your seed shopping well ahead of the Spring planting season. Shoot for 1-3 months before you will be planting the seeds. A couple years ago, I purchased seeds in January and had trouble finding a few varieties. This year I bought in early December and was able to source everything I was looking for. Be sure to account for possible delays in shipping and give yourself plenty of time to get what you need.
It takes some forethought and preparation to know what you’ll want to buy. However, if it’s closer to spring and you’re just now looking for seeds, don’t worry, you’ll be able to find plenty of things to grow.
There are so many places to purchase seeds from it’s difficult to decide the best place to purchase. Try a few vendors and see how you like their selection, speed of shipment, and customer service. Consider buying local and from small businesses. Buying local will ensure you find varieties that grow well in your area.
A few things to consider when shopping for seeds:
- Organic or Non-Organic – This is really up to your personal preference. Just know that organic seeds can come at a cost and not all varieties can be found as organic seeds. The seed origin may be less important than how the plant is grown. Buying non-organic seeds is not the end of the world if you end up growing the plant organically. Again, this is up to personal preference, you may not be concerned about this at all.
- GMO – Different than organic, be sure you understand that there is a difference. Seed companies CANNOT SELL GMO SEEDS to the general public. Some seed suppliers will put a non-GMO label on their packaging. That is most likely for marketing and to cut down on the number of inquiries the company must handle.
- Heirloom or Hybrid or Both – This could be a long discussion; I’ll try to paraphrase. There is room for both types in any garden. I recommend doing your research to figure out what you prefer. Check out this article from Burpee for more information
- Heirloom varieties are open pollinated varieties that have been preserved over generations. Seeds collected from these plants carry most of the characteristics from the parent plants. Many gardeners feel heirlooms have superior flavor and are dedicated to continuing to preserve them.
- Hybrids were developed to make large scale farming easier and more profitable. There are several reasons these varieties are chosen. They can be more disease resistant, more uniform, and heavy producers, to name a few. Hybrids are NOT genetically modified. They have been cross-bred with other varieties to boost certain characteristics.
These are suppliers that I’ve used. I have no affiliation with any of them at this time.
Some other ways to get seeds are local and online seed exchanges, garden stores, some hardware stores and groceries, inquire at farmers markets, and ask friends who garden. A word of caution, whenever pursuing an online source, use common sense and be sure they are reputable.
Supplies Needed for Seed Starting
When you begin to start seeds indoors it can feel overwhelming to think of all the equipment you may need. In your research you may see fully equipped setups with shelves and lights and trays and all the things. While these things are nice and may make your seed starting easier, you don’t have to get carried away with buying all of this stuff when you are first starting out. And you can often find reasonably priced kits that will have a fair amount of what you’ll need.
Also, get creative with what you already have in your house. A desk lamp can be repurposed as a grow light. Food containers like yogurt cartons, plastic cups, berry containers, and aluminum trays can be used as pots and seed trays. You can also put seedlings in a windowsill for light and warmth.
Below is a list of supplies that can be helpful when seed starting indoors:
- Pots:
- 1.5” – 2” seedling pots, OR multi-cell seedling trays. Typically these are most economical purchased from a local garden center.
- Repurpose dairy containers by poking holes in the bottom.
- Peet pots are also an option, they are made of pressed and formed biodegradable material. These pots are good for plants that have sensitive roots like squash and cucumber. They can be placed directly into soil without removing the plant from the pot. Please note, these pots can break down when saturated with water and can be messy.
- Seed Starter Soil Plugs
- Plant Tags – Plant tags are a must for identifying what you’ve planted and where.
- Plastic plant markers
- DIY – Cut a milk jug into strips about ½” wide by 4” long cutting one end into a point. They can be made from other plastic containers as well, preferably food grade.
- Popsicle sticks are also a great option.
- Masking tape can be used on the side of a pot or seed tray in lieu of plastic tags. When transplanting into the garden you may want a tag that you can stick into the soil
- Permanent Marker – Get a good permanent marker for labeling. I recently discovered Sharpie Fade Resistant that is UV and water resistant. This is great for when you move the plants outdoors.
- Seed trays and Humidity Domes:
- Sturdy trays without holes are great for holding several seedling pots. Some trays come with humidity domes or domes can be purchased separately. Domes aren’t completely necessary. They are used in the germination period to keep heat and moisture in the soil. Once seedlings sprout the domes are removed so there is no barrier to the light source and airflow.
- Aluminum tray – Inexpensive but less sturdy
- DIY Dome – Cut a milk jug in half or use a plastic cup as a makeshift dome.
- Dibber – A dibber is a tool that comes in different sizes that has a conical shape that sometimes has depth measurements on it. This tool is used to poke the soil creating a divot or hole to drop seeds into. You can also use your finger and don’t need to buy an extra tool. However, the larger ones are great for firmer soil and planting large seeds like garlic and beans.
The following list is for optional equipment that will be covered in more detail in the upcoming article Planting Seeds & Caring for Seedlings:
- Grow lights
- Heat mats & Heat Mat Thermostat Control
- Watering
- Power strip
- Light timer
- Shelves
Preparing Pots and Trays
Now that you have your pots and trays, be sure they are clean. Wash pots and trays with warm water and a mild soap and rinse completely.
Prior to planting, spray the pots and trays with an antibacterial spray and allow to dry completely. An antibacterial soap could be used at the washing stage to eliminate this step.
Sanitizing the pots is important when you reuse pots year after year, it keeps disease and fungus from infiltrating new seedlings. Notice, you can use pots repeatedly, don’t throw them out.
If you are using food containers as pots such as plastic cups and yogurt containers, be sure to poke several holes in the bottoms. The holes allow for water drainage.
Arrange the pots in your trays, if you have them, to sort out how things will fit. And you’re ready to start filling the pots with growing medium.
Growing Medium
Seeds have everything they need to start their little lives. They have all the fuel and food they need to get started, isn’t that amazing! To give the tiny seeds the best chance, it’s a good idea to start them in rich, fluffy soil. Seed starting medium can be a pre-packaged seed starting mix, coco coir, peat moss, compost, potting soil, or a combination of a few of these, which is my preference.
A good mixture for seed starting is:
20% Potting Soil
20% Worm Castings or sifted compost
Seed starting mix is a fine textured soil that is light and fluffy. Potting soil contributes aerators like perlite and vermiculite that help with moisture retention and air flow. Worm castings and/or compost provide seedlings with their first hit of dense nutrients after they’ve sprouted.
If starting in a single medium is your preference, try seed starting mix or compost. Potting soil often has fertilizer in it and on it’s own can burnout seeds.
If any prepackaged soil you purchase has large woody pieces in it, you should sift them out. The woody pieces take up too much room in seed pots and create a harsh surface that can damage roots. This is a fussy little detail but it does help.
Preparing the Seed Starting Mix
There is a little preparation to be done before the soil is ready to use.
Seedlings can die because of damping off. This is caused by pathogens that are present in the soil that can weaken seeds before they germinate and seedlings after germination. To prevent this, seed starting soil can be sanitized, killing fungus and pathogens.
There are a few different methods for this including heating the soil different ways; in the oven or microwave and steaming the soil. There are also ways to sterilize with chemicals, however, I don’t recommend using harsh chemicals on soil you grow food in.
I prefer using boiling water. This method is easy because it serves two purposes at once, to kill pathogens and to moisten the soil.
Put your seedling mixture into a large container like a plastic bin or metal trash can. Boil a large pot of water and pour the water into the soil. Mix the soil and water with a rake or shovel until the water is completely distributed and the soil is moistened. Allow the soil to cool down before planting, heat can kill your seeds.
Seeds Need Moist Soil
Let’s talk about soil moisture. It’s a good idea to plant seeds into moist soil because it aids in gemination. If the soil is sufficiently moist you may not have to water right after planting, seeds have less of a chance to be washed away, especially surface sown seeds. Moist soil helps tiny seeds to stay put.
When the soil has the right moisture content it will hold together when squeezed in your hand. Be careful it’s not soaking wet or muddy. It should be light and fluffy. Again, if sanitizing with boiling water, allow it to cool before you add seeds.
Now it’s time to plant…. In the next article of this Seed Starting Series we will be discussing how to plants seeds, set up a seedling station, and care for seedlings. Stay tuned!
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