Starting seeds is an exciting time for any gardener. Seeing those first tiny seedlings emerge brings hope for the bounty to come. But getting seeds off to a good start requires having the right soil mix. When it comes to starting vegetable seeds, not just any potting soil will do.
Why Seed Starting Mix Matters
Using a properly formulated seed starting mix is important for several reasons
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It is lightweight and fluffy, allowing delicate roots to easily grow and spread Regular potting soil can be too dense
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It retains moisture but also drains well, providing the right balance seedlings need.
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It is sterile, reducing the chance of diseases.
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It has a neutral pH that is ideal for seed germination.
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It has a fine texture so tiny seedlings are not overwhelmed.
Go Organic Whenever Possible
When buying a commercial seed starting mix, choose an organic option if you can. Organic mixes do not contain synthetic chemicals or fertilizers that could harm young seedlings. Look for mixes certified by OMRI (Organic Materials Review Institute).
You can also easily make your own organic seed starting mix at home.
How to Make Your Own Seed Starting Mix
Making your own organic mix is simple and ensures you get a high-quality soil. Here is an easy homemade recipe:
Ingredients:
- 1 part compost
- 1 part coconut coir or peat moss
- 1 part perlite or vermiculite
Steps:
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Mix equal parts compost and coconut coir or peat moss in a large container. Use a fork or your hands to blend thoroughly.
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Add equal parts of perlite or vermiculite and mix again. These provide air pockets in the soil.
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Moisten the mix with water until it is consistently damp but not soggy. It should clump together slightly when squeezed.
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Allow the mix to sit for 1-2 days so the ingredients fully blend.
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Use your homemade mix to start seeds!
This simple 50/50 blend of compost and peat/coir with perlite/vermiculite creates an ideal seed starting soil. Customize it based on what materials you have available.
Tips for Your Homemade Mix
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Use high-quality compost from your own compost bin or purchase organic compost. This brings nutrients and beneficial microbes.
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Coconut coir is more sustainable than peat moss. It also resists compaction better.
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Mix in a bit of worm castings for added nutrients if desired.
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Don’t use garden soil which can contain diseases, pests, and weed seeds.
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Avoid contaminated compost that could have chemicals or trash.
Testing Your Seed Starting Mix
How can you tell if your seed starting mix is well formulated? Here are a few simple ways to test it:
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Look: Good mixes will be light, fluffy, and fine-textured. Wet a handful and squeeze – it should barely clump.
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Feel: There should be a nice balance of moisture retention and quick drainage when wet.
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pH: Test strips can confirm the pH is around 6.5, ideal for seeds.
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Grow: Plant a few test seeds and ensure they germinate well and seedlings grow strongly.
Adjust your mix as needed based on these tests for optimal seed starting power. With the right soil, your vegetable seeds are sure to thrive!
When to Use Seed Starting vs. Potting Mix
It’s important to understand when to use a seed starting mix versus a potting mix:
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Seed starting mixes are used for starting seeds and cuttings. They are lightweight and sterile.
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Potting mixes are used for transplanting seedlings into larger containers. They contain more nutrients for established plants.
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Seed Starting Mix: Seeds and cuttings
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Potting Mix: Transplanting seedlings
Don’t use regular potting mix to start seeds or the denseness can inhibit germination. And don’t use seed starting mixes for long term potting or they lack nutrients.
Best Vegetables to Start from Seed
Many common vegetable varieties grow best when started from seed rather than buying transplants. Here are some top vegetables for starting from seed with the proper soil mix:
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Tomatoes – Start 8-10 weeks before transplanting. Choose small determinate varieties.
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Peppers – Need 10-12 weeks before transplanting. Start indoors in warm spot.
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Eggplant – Grow for 8-10 weeks indoors before moving outside.
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Broccoli/Cabbage – Grow for 5-7 weeks indoors before transplanting.
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Cucumbers/Squash – Start 3-4 weeks before outdoor planting. Use peat pots.
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Carrots – Can be directly sown outside but starting seeds inside gives a head start.
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Beans – Best direct sown but can get an early start indoors.
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Peas – Direct sow outside once soil thaws. But can start early indoors.
Play around with different vegetables to see which you prefer starting from seed yourself. Just be sure to use seed starting mix for best results.
Common Problems When Starting Seeds
Even with the proper soil, problems can pop up when starting vegetable seeds. Here are some common issues and solutions:
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Leggy seedlings – Plants stretch for light from low light or high temps. Provide ample sunlight or cooler temps.
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Damping off – Fungus kills seedlings at soil line. Use sterile mix and avoid overwatering.
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Poor germination – Seeds fail to sprout due to improper planting depth or old seeds. Plant at correct depth and use fresh seeds.
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Root crowding – Roots entangle when seedlings get pot bound. Transplant on schedule into bigger containers.
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Insect infestations – Fungus gnats or other pests can plague seedlings. Use screens to keep out insects.
Pay close attention to your seeds and seedlings to catch any problems early. Take corrective action right away to get your vegetable plants off to a vigorous start.
Frequently Asked Questions
Here are answers to some common questions about seed starting mix:
What is the difference between seed starting and potting mix?
Seed starting mixes are lightweight, sterile blends designed specifically for starting seeds. Potting mixes are denser with more nutrients and made for transplanting established plants.
Is homemade or commercial mix better?
Homemade mixes allow you to control the ingredients but commercial mixes provide convenience. Both work well when formulated properly.
How long does seed starting mix last?
Plan to use seed starting mixes within 1-2 years before replacing. The nutrients and beneficial microbes decline over time.
Can you reuse seed starting mix?
It’s best to use fresh, sterile mix each season. Reusing mix increases the chance of diseases carrying over.
What can be used instead of peat or coir?
Good alternatives include shredded leaves, straw, grass clippings, paper strips, or bark fines. But peat and coir work well when sourced sustainably.
Can I start seeds in eggshells?
Yes! Fill eggshells with seed starting mix and place in an egg carton. The shells provide added nutrients as they break down over time.
When should I start seeds indoors?
Check the seed packet for recommended timing. In general start slow growers like peppers and tomatoes 6-8 weeks before your last expected frost. Quick growers like lettuce can be started just 2-3 weeks before transplanting outside. Stagger your plantings over several weeks for a continuous harvest.
Get the Best Start with Seed Starting Mix
Creating an ideal soil environment is crucial when starting vegetable seeds. Follow this guide and your seeds will thrive and grow into healthy, productive plants! Be sure to use a properly formulated seed starting mix, test for quality, and troubleshoot any issues that emerge. Your garden will flourish when you get your plants off on the right foot.
Looking to make your own indoor seed starter system? Learn how to mix the best soil for starting seeds and learn the seed starting basics.
Looking to make your own indoor seed starter system? Learn how to mix the best soil for starting seeds and learn the seed starting basics.
After the warmth of holiday gatherings and festivities, planning for spring comforts us in the cold, short days of winter. Apart from the satisfying process of nurturing little green seedlings under your roof, practical reasons exist to start some of your seeds indoors. First, well-established young plants will produce earlier, thus giving you a longer picking season. In Northern states, such as Pennsylvania, where I live, we start heat-loving, long-season crops such as okra and eggplant indoors if we are to expect anything from them before Labor Day.
Second, many of us routinely start garden plants indoors — rather than buying seedlings from a nursery — to take advantage of special varieties available only from seed companies. Whatever your requirements — tomatoes for drying, storage or exceptional flavor; white eggplants; seedless watermelons; long-keeping cabbage; hot peppers; slow-bolting lettuces — these and many more vegetables with special qualities can be yours if you grow the plants from seed.
Unless you have a greenhouse or a large bank of fluorescent lights, you’ll want to be selective about the varieties of vegetables, herbs and flowers you start at home. Pick ones that will benefit the most from an early start. Given space for only a few, I’d choose tomatoes, eggplant, peppers and cabbage; basil and parsley; and snapdragons and dahlias.
Several others, including beets, Brussels sprouts and Chinese cabbage, don’t necessarily need a head start indoors, but I have done so on occasion. Beets need to be thinned, and they are sensitive to toxins in the soil. Brussels sprouts reach their best flavor in fall from spring planting. If you start Chinese cabbage early, sow it in individual pots because transplanting sometimes can make it bolt to seed prematurely.
The following vegetables are not usually recommended for indoor seed sowing: asparagus, snap beans, lima beans, carrots, corn, endive (best in fall from spring outdoor sowing), parsnips (best eaten in fall), radishes, spinach (seeds germinate well in cool soil), soybeans, Swiss chard and turnips. Herbs that fit in this category include dill, cilantro and summer savor.
Indoor Seed Starter System: How to Begin?
Your seed orders have arrived and you’re ready to plant. First, gather your containers. These can be special seed-starting flats, cubes or other systems ordered from a catalog; flats made from scrap wood; or a cobbled-together assortment of cut-down milk cartons, used aluminum pans, chipped pots, cottage cheese tubs, etc.
Like many gardeners, I used a motley collection of wooden flats, purchased trays and household discards when I had a home greenhouse with plenty of space. Now, my plant-starting space is more limited, so my system consists of one or two 10-row, commercially made plastic flats — rather flimsy things with narrow, three-fourths-inch-wide rows. Each flat is set into a 12-by-22-inch plastic tray; the 10-row flats are perforated but the trays are not. Soon after the seeds germinate, I transplant the seedlings into individual cells in four-, six- or eight-cell market packs saved from nursery purchases and donated by friends.
With this system, I can plant 20 kinds of tomatoes by putting a cardboard separator in the center of each row, and because the sections are small, I waste less seed as I’m not tempted to overplant.
Homemade scrap wood flats can be any size that fits your available space, with two exceptions: Not too large or they’ll be too heavy to lift when full of soil, and no more than 2 to 3 inches deep. Deeper flats waste potting soil, and too-shallow ones limit root development and dry out prematurely. Leave one-eighth-inch spaces between the slats on the bottom of a homemade flat to allow for drainage. I usually line mine with several sheets of newspaper to keep soil from washing through the bottom wood strips.