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The Best Seed Starting Mix for Indoor Gardeners

Having a good seed starting mix is almost as important as the seeds themselves. It’s the medium that allows seeds to germinate and sprout healthy growth.

A tray of basil seedlings.  Seeds need seed starting mix to get a good start on growing into healthy plants.

While you may have some success with regular soil, seed starting mix provides optimal texture, nutrients, and drainage for seeds. You’ll be surprised how the germination rate increases when you place seeds in this specialty mix.

In this post, I’ll go over the seven best seed starting mixes. Keep reading to learn more!


Best Seed Starting Mix Summary

Here’s a quick comparison of our picks for the best seed starting mixes out there. Keep reading for more information about what makes a good seed starting mix and for a more in-depth profile of each selection.

Name

Hoss Premium Seed Starter Mix

Jiffy Natural and Organic Seed Starting Mix

Sungro Black Gold Seed Starter Mix

Espoma Organic Seed Starter

Miracle-Gro Seed Starting Mix

Hoffman 30103 Seed Starter Soil

Burpee Organic Coconut Coir

Awards

Description

Lightweight, natural ingredients

Organic ingredients including vermiculite

Ingredients aid in water retention. 

Great for organic gardening 

Uses: Seed starting and potting up seedlings

Offers moisture retention, pH balance

Sold in dehydrated brick form

Pros

Brand know for high-quality products

Budget-friendly

Mix is sifted twice

Includes beneficial mycorrhizae fungi

Includes nutrients

Satisfaction guarantee or full refund

100% biodegradable

Cons

None

May contain large pieces of matter

None

Can dry out quickly

May have to remove large pieces

Pricey

Has to be rehydrated before using

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Characteristics of Good Seed Starting Mix

Natural Ingredients

Most seed starting mixes will contain natural ingredients that help retain moisture while still providing good drainage.

Here are some common ingredients you’ll find in a good starter mix:

  • Peat moss
  • Coconut coir
  • Perlite
  • Vermiculite
  • Worm castings
  • Bone meal

Fine Texture

Depending on what you’re growing, some seeds are so small, they could easily be mistaken for a speck of dirt. It’s amazing how something that starts off so small can sprout into healthy vegetables and flowers!

That’s why it’s ideal to have seed starting mix with a fine texture. This allows even the smallest of seeds to be able to germinate and push through the soil. It also helps establish roots easily.

Seed starting trays have small cells, and unsifted soil could leave air pockets. Large air pockets will keep seedlings from receiving the hydration and nutrients they need.

Good Drainage

As previously mentioned, seed starting mix must have good drainage. If your mix contains the proper ingredients, you usually won’t have any trouble with this.

This is also why you should try to avoid any heavy potting soil. It can often be packed down by water and won’t dry out as quickly when growing indoors.

Appropriate Amount of Minerals and Nutrients

You may think that seed starting mix should contain an optimal amount of nutrients. But, in reality, seeds shouldn’t germinate in nutrient-heavy soil. This can overwhelm seedlings and cause them to burn.

As the seedlings grow and are ready to be potted up, they can transition to a more nutrient-dense potting soil.


The Seven Best Seed Starting Mixes for Indoor Gardeners

Best Overall

Hoss Premium Seed Starting Mix

My top choice overall for the best seed starting mix is Hoss’ Premium Seed Starting Mix. Hoss is a great brand, known for quality products. Their premium seed starter mix is no different.

This mix contains over a dozen natural ingredients. Of these ingredients, you’ll find coconut husk peat, worm castings, perlite, compost tea, greensand, kelp meal, and more. It’s not often that you find so many beneficial ingredients in one mix.

Even though it has several ingredients, the mix is still lightweight with good drainage. But, it also still retains enough moisture to avoid constant dry-out.

This mix is also cost-friendly, staying under $25 for the largest bag.

Pros:

  • Several beneficial ingredients
  • Lightweight
  • Cost-friendly
  • Successful germination for reviewers

Cons:

  • None

Best for Root Formation

Sungro Black Gold Seed Starting Mix

Sungro Black Gold Seed Starting Mix contains four helpful ingredients for starting seeds. These include peat moss, perlite, dolomite lime, and an organic wetting agent.

All four ingredients help with water retention, so you won’t find dried-out seed trays every time you visit.

Sungro Black Gold is double-screened, meaning it’s sifted twice to get only the finest ingredients in the mix. This helps seedlings easily form roots without the pressure of heavily packed soil.

The perlite beads are also helpful in keeping the growing medium from becoming packed. They break up the other ingredients to promote airflow around the roots.

The 16-quart bag can fill 162 cells within Hoss’ seed starting trays. That’s quite a start to your garden!

Pros:

  • Great for root formation
  • Good water retention
  • Lightweight
  • Sifted twice

Cons:

  • None

Best Organic Mix

Espoma Organic Seed Starter

Espoma Organic Seed Starter Premium Potting Soil Mix - All Natural & Organic Seed Starting Mix with Mycorrhizae. For Organic Gardening, 16 qt, Pack of 1

Espoma Organic Seed Starter is a great choice for organic gardeners. The seed starting mix combines sphagnum peat moss, perlite, and lime.

The peat moss and perlite help with water retention, similar to other brands. The added lime helps control the pH of the starter mix. This helps seedlings absorb and retain nutrients as they grow.

Along with these ingredients, Espoma includes mycorrhizae in its mix. These are beneficial fungi that aid in root growth and development.

Espoma guarantees that no harsh chemicals or synthetic plant food is included in their mix. It’s also sustainably made in the USA.

Pros:

  • Fully organic
  • Made in the USA
  • Includes mycorrhizae
  • Added lime for ideal pH levels

Cons:

  • Some reviewers had trouble with the mix drying out quickly

Best for Potting Up

Miracle-Gro Seed Starting Mix

Miracle-Gro Seed Starting Potting Mix, 2-pack 8 qt., For Use in Containers

Miracle-Gro’s Seed Starting Mix is a great medium to use when moving your seedlings to a larger pot. Along with peat moss, perlite, and a wetting agent, Miracle-Gro includes a small amount of their plant food.

Normally, I would not recommend adding plant food/fertilizer to a starter mix. But, the plant food is such a small percentage of this mix that it won’t hurt your seedlings.

To be safe, I do recommend using this once your seeds have become seedlings. But, this is still a great option to start seeds in as well. You’ll have strong, healthy seedlings ready to be transported to the garden.

Pros:

  • Great for potting up seedlings
  • Includes a healthy amount of nutrients for seedlings
  • Cost-friendly

Cons:

  • Some reviewers had to sift out larger pieces

Best Budget Choice

Jiffy Natural and Organic Seed Starting Mix

Jiffy Natural & Organic Seed Starting Soil Mix, 10 QT, 2-Pack

Jiffy Natural and Organic Seed Starting Mix is the best budget-friendly choice. For around $15, you get 10 quarts of starter mix. That’s a good amount to get your garden started with.

The contents of Jiffy’s mix are similar to the Espoma brand. Both contain peat moss and lime for pH control.

Jiffy’s mix does use vermiculite instead of perlite though. This will help more with water retention rather than aeration. So, it’s a good choice if you live in a dry area.

Jiffy is also known for their peat pots, which can be directly planted into the soil. Combining their seed starting mix with their peat pots, you can easily transplant seedlings without the worry of shock.

Pros:

  • Cost-friendly
  • Good moisture retention
  • Great for transplanting

Cons:

  • Some reviewers had to sift out larger pieces

Best for Customer Service

Hoffman 30103 Seed Starter Soil

Hoffman 30103 Seed Starter Soil, 10 Quarts

Hoffman’s 30103 Seed Starting Soil isn’t really soil at all. This mix contains peat moss, vermiculite, limestone, and a wetting agent. This mix holds moisture well, while maintaining a balanced pH level for seedling health.

Honestly, it sounds very similar to all the other mixes listed. So, what makes Hoffman stand out? Their satisfaction guarantee.

If you aren’t impressed with how their mix works, you can request a full refund. That’s comforting when you’re taking a chance on a new brand. But, by reading reviews on this product, most reviewers are more than happy with their germination results.

Pros:

  • Made in the U.S.A.
  • Satisfaction guarantee
  • Good moisture retention

Cons:

  • Pricier than other brands

Best Concentrated Mix

Burpee Organic Coconut Coir

Burpee Organic Coconut Coir Concentrated Seed Starting Mix, 16 Quart

This seed starting mix looks a little different than its competitors. Instead of coming in a bag, Burpee’s Organic Coconut Coir comes as a dehydrated brick.

All you have to do is add water and watch the mix expand. What started as a brick will turn into eight quarts of lightweight seed starting mix. The coir holds moisture, and it combines great with potting soil when transplanting seedlings.

You can purchase two eight-quart bricks for $11, so it’s a cost-friendly product. The coconut coir is also 100% biodegradable, so you’re making an eco-friendly choice with this mix.

Pros:

  • Biodegradable
  • Cost-friendly
  • Easy to store

Cons:

  • Extra step required to hydrate the mix

FAQs on Seed Starting Mix

Is seed starting mix necessary?

There’s no hard and fast rule that says you have to use a seed starting mix. Just like you direct sow some seeds into the garden, seeds can have successful germination in regular soil. Some gardeners just choose to use a potting mix.

But, if you’re wanting your seeds to have the best chance at germination, I recommend using a specialty starter mix.

Some seeds will easily germinate without much fuss. But, seed starting mix comes in handy when you start playing with pickier vegetables and flowers. They won’t have to work hard to form roots, and the seeds won’t be overwhelmed by nutrient-dense soil.

What’s the difference between potting soil and seed starting mix?

If you search seed starting mix, you may see some potting soil mixed in with the product results. While you can use potting soil, it’s not the same as starter mix.

Seed starting mix should not contain actual soil. As previously discussed, starter mix contains natural ingredients like peat moss, perlite, vermiculite, and bone meal.

A good starter mix will also have a fine texture with little-to-no nutrient add-ins.

Potting soil, on other hand, will contain some type of soil. Since its primary use is not seed starting, the texture will be coarser. This is great for potting up seedlings.

Potting soil also usually contains some type of fertilizer. So, it’s best to wait and use it until your seedlings are established.

How do I avoid the seed starting mix drying out?

Many gardeners have trouble with seeds drying out when growing indoors. A helpful trick is to wet your seed starting mix before you fill your seed trays.

Place your starter mix in a large bowl or bucket. Slowly add water to the mix until the consistency is similar to peanut butter. Then, fill your seed trays with the mix.

This helps establish good water retention. You will then routinely water your seedlings to keep them healthy and happy.


Use the Best Seed Starting Mix for Your Indoor Gardening

Using a seed starting mix will help you germinate healthy seedlings that transplant well. My top pick overall for the best seed starting mix is Hoss’ Premium Seed Starting Mix. It has so many beneficial ingredients, and its price is competitive with all other brands. But, any of these mixes is a great choice!

At Minneopa Orchards, we’re helping you create a successful garden this year. Visit our Seed Starting page where you’ll find out other posts for the best products to use along with helpful growing advice.