We’re in the process of starting most of our seeds indoors to give them a nice strong start before it’s time to transplant them in the garden. Giving your plants this important head start helps them really take off when they get planted outdoors, and gives you a better chance at a larger harvest. In our case, it’s just a little extra luck on our side since we’re pretty unfamiliar with the new growing zone we just moved into here in South Carolina. The fun part about starting seeds indoors? After planning and dreaming about your garden all winter, you finally get your hands dirty again and take yourself closer to summertime!
Which Seeds to Start Indoors, and When
Some seeds such as lettuce mixes, arugula, dill, rutabaga, carrots, parsnips, beets, cucumbers and peas like cooler weather conditions and are recommended to be planted directly into the ground as soon as the soil starts to warm up and is workable. Below are the seeds that we started indoors, with the recommended times to plant (before the last expected spring frost date.)
- Peppers – bell peppers and jalapeños (8 weeks before last frost)
- Broccoli (6-8 weeks)
- Tomatoes (6-8 weeks)
- Basil (4-6 weeks)
- Chives (4-6 weeks)
- Cilantro (4-6 weeks)
- Spinach (4-6 weeks)
- Winter squash (4-6 weeks)
- Pumpkin (3-4 weeks)
- Parsley (2-4 weeks)
- Chard (1-2 weeks)
Assuming that you’ll plant your seedlings outdoors about 2 weeks after your last expected spring frost date (if you’re unsure of that date, you can do a search on NOAA’s site) you can calculate approximately when to start your seeds.
Types of Containers
There are lots of different options for seed starting containers, from milk cartons and yogurt containers to aluminum disposable pans, bricks and plastic greenhouse trays, to homemade wooden flats. You’ll just want to make sure that the container is at least 3 inches deep. We chose homemade wooden flats because they’re easy and inexpensive to make, and they’ll last forever. They’re a bit heavy, but the stability of them is nice if they need to be moved. I have 3 flats which each are 12″ x 16″ and 4″ deep. They sit side-by-side on a craft table in a warm room in our house.
To make the flats, we cut 1″ x 4″ cedar boards (naturally rot-resistant) to size and pieced them together with screws. We left 1/8″-1/4″ slats on the bottoms to allow for water drainage.
Seed Starting Mix
A good medium for starting seeds is light and porous. You can buy seed starting mixes at your local garden center. We made ours out of these 3 ingredients that we already had at our house: 1 part loose organic garden soil, 1 part compost and 1 part vermiculite.
I lined the bottoms of our flats with a layer of newspaper and covered that with 1/2″ of milled sphagnum moss to help hold the soil if water drains out.
The Soil Block Method
My mom was telling me how my grandpa started his seeds, and I remember his garden being absolutely amazing, so I use as many of his methods as I can! He used a soil block tool (like this one) to make individual seed starting cubes in his flats. It’s really cool because it spaces the 2″ cubes out just right and makes a little nest in each cube to drop the seeds into. Here’s how you make the blocks:
- Using a big tub, gradually add water to your soil mix until it’s the consistency of peanut butter.
- Pack the 4-cube block maker with soil mix and use your hands to make sure it’s filled up and leveled off on the bottom.
- Press down the handle on the top of the tool to eject the cubes into your flats.
- Let the cubes sit for a few hours to dry a bit before planting seeds in them.
Making the blocks is definitely a little time consuming and messy, but I love it. It saved me time in the long run, as it was easy to drop the seeds into the already formed cubes. I also have a touch of OCD when it comes to organization, so I think the nice and neat rows are awesome. It’s easy to lift them out of the flat to transplant them when the time comes.
Planting Your Seeds
If you use the soil block method, drop 1-3 seeds into each nest in the cubes. In containers other than soil blocks, you’ll want to make a furrow that’s about 1/4″ deep to place your seeds into. For small-sized seeds, plant them 1/8″ apart, 1/2″ for medium and 1″ for large. Cover the seeds lightly with soil mix; it’s fine if it’s dry. Seeds should be covered to a depth of 3 times their size. We use popsicle sticks to label them. Cover the flats with aluminum foil to help them retain moisture and set them in a warm spot for germination. Check often to make sure the soil mix doesn’t dry out. It should be moist but not soggy. It’s easiest to lightly water by using a spray bottle so the seeds won’t float away.
Once our seeds germinate, I’m going to write my next post about how to take care of the seedlings. When you see the first little shoots of green pop out of the soil, they need to be given light. 12 to 16 hours of light per day is ideal. Stay tuned for my next seed starting post!
Have you started seeds indoors? What methods did you use?
Other posts in this series:
- Starting Seeds Indoors: What to Do When They Sprout
- Starting Seeds Indoors: How to Transplant Your Seedlings
- Moving Your Seedlings Outdoors
- How to Give Seedling Plants a Strong Start in the Garden