6 Steps for Starting Seeds Indoors
We can all agree the benefits of growing a garden are endless, but watching a seed you nourish turn into a full grown plant is rewarding, educational, and empowering. When you plant from seeds, you’re not just limited to what plants are for sale at your local nursery, the entire seed catalogue becomes open to you.
Starting seeds indoors gives your crops a head start on the growing season, with earlier blooms and harvests in the spring and summer. Those plants will also be stronger and more well adapted to your specific climate. All it takes is a few basic guidelines to master this cornerstone skill of gardening.
Choosing Your Seeds
In order to successfully start any seeds indoors, starting with good quality seeds is key. Check the back of the packet to make sure your seeds were packaged for the current growing season, and if they weren’t, ensure they’ve been stored in a cool, dry and dark place. Seeds already exposed to heat, moisture and light won't be as vigorous because your seeds are actually alive - those small, brown, dried little guys are actually breathing and absorbing moisture from the air.
Planning Your Garden
Before you purchase your seeds, take some time to plan out what you want to grow. Some seeds are Easy to Grow, some are Container-Friendly, and there are seeds best planted in both the Warm and Cool Seasons.
Next, find the average last frost date of the area you live in. A frost date is the average date of the first or last light freeze that occurs in spring or fall, and most seeds should be started 6-8 weeks before your last frost date. This gives the plants plenty of time to grow large and healthy enough to survive their eventual transplanting to the garden.
| Vegetable | # of weeks before last Frost Date |
| Tomatoes: | 6-8 weeks |
| Peppers: | 8-12 weeks |
| Lettuce: | 4-6 weeks |
| Herbs: | 4-6 weeks |
| Wildflowers: | 4-6 weeks |
| Melons: | 2-4 weeks |
You can also plan to stagger some of your sowings every 2 to 4 weeks so you’ll have just the right amount of crop over a long season, instead of all at once. This method works great with tons of crops, like lettuce, radishes, broccoli, beets, carrots, and turnips.
Choosing Your Containers Soil
Nearly any type of household container can be used for starting seeds: yogurt cups, egg cartons, milk jugs, water bottles, toilet paper rolls, etc. In addition to these DIY options, plenty of store-bought seed starting kits are available with everything you need. Regardless of what you use, you’ll want your container to be around two inches deep and have adequate drainage.
Though just as many options seem to be available for the seed-starting soil, this choice is a little more important. The mix your seeds are first grown in is what will provide nutrients, water, air, and warmth to your young seedlings - making it a critical part of the process.
Steer clear of regular outdoor gardening soil, as it’s typically too dense, doesn’t drain well, and will often harbor diseases that young seedlings can’t fight off. A good mix will have a fine, yet fluffy texture that holds moisture well but also drains well. Some mixes come with nutrients included, and others require you to add your own. Take note of which you are using and experiment until you find what works for you.
Planting Your Seeds
Fill your chosen containers with your seed starting mix, and make a small indentation in the center for your seed. While the depth of this hole depends on the size of the seed, the ideal depth is 2-3 times the width of the seed.
Tomato seeds are pretty small, usually about ⅛ inch, meaning they should be planted about ¼ inch deep, while bush bean seeds are larger, sometimes nearly ½ inch wide, and should be planted much deeper to about 1.5 inches. Check the back of your seed packet for its individual specifications.
Place two seeds in each hole, so if one doesn’t germinate, you’ll have the other one as a backup. If they both germinate, you’ll remove the smaller or weaker looking seedling.
Cover the seeds with just enough soil and very gently compress the mixture. By very gently compressing the soil, you’re creating the proper seed-to-soil contact for the seed to absorb water.
Lastly, gently thoroughly water the soil until it begins to drip out of the bottom of your container.
Providing Warmth, Light, and Moisture
Warmth
An important part of coaxing your seeds to break through their outer shell and begin to sprout is providing enough warmth. Every seed has a different prefered temperature range for germination, which is generally warmer than when it’s a seedling. A good soil temperature range for most seeds to germinate is 75 to 90 degrees, and while it might be 75 degrees in your home, keep in mind the moist soil your seeds are in will make it cooler.
There are plenty of warm spots around your home for a good germination station, like above refrigerators or other heat producing appliances, near a south-facing window, or close to a heating vent or hot water heater. Heat-producing seedling mats are also widely available and provide a constant and reliable source of heat.
You can also create a small greenhouse around your containers by placing them inside a transparent bag or covering the top with plastic wrap. Just place the covered containers near a sunny window and the light will create heat under the plastic while also keeping the soil moist. Once the seeds start to germinate, remove the plastic to allow proper airflow for the seedlings.
Light
Though most seeds don’t require light to germinate, once they begin to sprout, it’s essential to provide them with plenty of light. Only south-facing windows that receive all day sun will have enough light for your seedlings, so if this isn’t an option, you’ll have to purchase a grow light. Just use one cool-colored light bulb and one warm-colored light bulb in the fixture and hang it a couple inches above your seedlings.
Moisture
While the initial watering you did when you first sowed your seeds should be enough to get them to germinate, your seedlings will require more and more water once they begin to grow. Your seedling’s roots need air just as much as they need water, so it’s important to keep the soil moist but not soaking wet. Allow the soil to dry slightly between waterings, and only water to the point that it begins to drip out the bottom of your container.
Continued Care and Transplanting
Make a habit of checking on your seeds every morning and observing them, taking a few notes, and water if needed. If you notice the soil drying out very quickly, or roots growing out of the bottom of their containers, it might be time to “pot up” and transfer seeds to a bigger container.
When it’s time to transplant, start by moving your seedlings in a slightly shaded area of your yard before to allow them to acclimate to the outdoor weather and sunlight.
When you’re ready to plant them into the soil, pop your seedlings out of their containers and gently loosen up their roots to encourage growth. Water the newly transplanted seedlings thoroughly and get ready to enjoy the fruits of your labor (pun intended).
Still have questions about this whole process? We get that it can be tough the first time around. You can contact us with any questions and we’d be happy to help you further.