While you can always go into a store to purchase a seed starting mix, it’s a great idea to make your own seed starting mix, so you know exactly what is contained in the soil.
So ideally, it is important to understand the components of seed starting mixes and the role that they play, so you know what you’re looking for when making the mix.
The ideal mix needs to strike a balance between water retention and drainage and also supply your plants with the nutrients that they need to grow healthy and strong before going out into your garden.
In the following guide, we’ll take a look at some of the best seed starting mixes out there and why you should be investing in them.
- Best Seed Starting Mix – Reviews For 2021
- Best Overall: Jiffy Natural & Organic Starter Mix
- Runner Up: Burpee 8 qt Organic Coir Compressed Seed Starting Mix
- Alternative: Hoffman 30103 Seed Starter Soil
- Alternative: Espoma SS8 8-Quart Organic Seed Starter
- Alternative: Burpee Organic Premium Potting Mix, 8 quart
- Seed Starting Mix FAQ
- Is seed starting mix necessary?
- What is the difference between potting soil and seed starting mix?
- How do you make a seed starter?
- Can you start seeds in the potting mix?
Best Seed Starting Mix – Reviews For 2021
Best Overall: Jiffy Natural & Organic Starter Mix
The organic seed starting Jiffy mix is a greenhouse quality mix that is 100% organic. It’s also pH balanced and contains a specially formulated soil that is enhanced with vermiculite, lime, and peat moss.
Some of the benefits of all of these ingredients are that peat moss holds up to 20 times its weight in water, providing aeration for plant roots and helping to retain nutrients that the plants need.
The vermiculite prevents soil compaction, retains moisture, and also improves aeration. It can also soak up to 3 to 4 times its volume in water. When it comes to lime, it promotes a healthy pH balance in the soil.
- 100% organic
- PH balanced
- Added nutrients
- Poor water retention
- Type: Wood
- Ingredients: Vermiculite, peat moss and lime
- Volume: 10 quart
- Best for: Cuttings
Runner Up: Burpee 8 qt Organic Coir Compressed Seed Starting Mix
The Burpee Organic Coir Compressed Seed Starting Mix is an excellent 100% biodegradable seed starting alternative soil mix. Made from coconut coir, which is a renewable resource made by recycling the husks from harvested coconuts, it provides excellent nutrition for your plants and seeds.
Ultimately, it provides a great and quality growing medium for various types of plant life. The compressed brick expands to about 8 quarts in a few minutes just by adding water.
- 100% biodegradable
- Harvested from a renewable resource
- Provides a quality growing medium for seeds
- Poor aeration
- Type: Coconut coir brick
- Ingredients: Coconut husks, plants
- Volume: 8 quart
- Best for: seeds and cuttings
Alternative: Hoffman 30103 Seed Starter Soil
The Hoffman 30103 Seed Starter Soil contains six components blended in proper proportions, is loose and fertile, and lightweight. It is a specifically formulated soilless mix that promotes superior germination of seeds.
It is also useful for transplanting or root cuttings. This potting and planting mix provides perfect air space and moisture retention for faster and stronger plant starts.
- Good moisture retention
- Strong and fast seed starts
- Contains sticks and stones
- Type: Soilless mix
- Ingredients: Good earth, vermiculite, limestone, peat moss
- Volume: 10 quarts
- Best for: seeds
Alternative: Espoma SS8 8-Quart Organic Seed Starter
The Espoma SS8 8-Quart Organic Seed Starter is formulated from 80 – 90% sphagnum peat moss. It also contains perlite, limestone to adjust pH, and yucca extract. This all-natural seed starting mix is ideal for seedlings and cuttings.
Ultimately, it helps to promote growth and improves moisture retention as well. The formulation is enhanced with Myco-tone, and ultimately is the best mix for organic gardening.
- Enhanced with Myco-tone
- Promotes root growth
- Takes a while for the mix to absorb water
- Type: Natural, organic
- Ingredients: peat moss, limestone and yucca extract
- Volume: 8 quart
- Best for: seeds
Alternative: Burpee Organic Premium Potting Mix, 8 quart
The Burpee Organic Premium Potting Mix is enriched with Burpee plant food for vibrant flowers and delicious vegetables and herbs.
Formulated from coconut coir, which is a sustainable and renewable resource, it helps to maintain moisture between waterings for beautiful flowers and delectable vegetables and herbs.
It’s ideal for raised bed gardening and container gardening as the growing mix feeds plants instantly and provides slow-release plant food that feeds plants for up to three months.
- Requires less water
- Slow-release plant food
- Formulated with coconut coir
- Contains gnats
- Type: Organic
- Ingredients: Coconut coir, plant food
- Volume: 8 quart
- Best for: cuttings and seeds
Seed Starting Mix FAQ
Is seed starting mix necessary?
While seed starting mix is not soil, they are blended to create a thriving environment to get seeds germinated and into the seedling stage. This is the stage where you will transplant into potting soil or garden soil.
Seed mixes can be made of various ingredients and components, and there are various different kinds. However, not everyone requires seed starting mixes because some gardeners do very well starting their seeds in potting soil or rich garden soil.
Ultimately, this saves the work and stress of transplanting but if you need sterile soil because of fungi or mold concerns, then seed starting mixes make an excellent choice and will really help you out.
Some gardeners choose to just trust a sterile seed starting mix and have good results for their garden.
What is the difference between potting soil and seed starting mix?
The primary difference between seed starting mix and potting soil is that potting soil requires nutrients for the plant to grow, and seed starting mix does not require any nutrients.
In fact, seeds germinate and grow their first set of leaves without any added nutrients to the soil.
This is because the seed itself is jam packed with nutrients that the plant uses to get off to a good start. So one of the biggest mistakes that people make is buying synthetic fertilizer and using it on little seedlings too early.
Seedlings don’t require a lot of fertilizer. However, if you still feel the need to fertilize, then you should only use about a quarter of the strength as directed on the package. Ultimately, the beauty of organic fertilizers is that plants cannot be harmed, and they will decide when they need to start using the extra fertilizers.
So the same mix that you use for potting soil can also be used for seed starting. The compost and worm castings will feed the plant at the appropriate time. It’s also much more convenient to just make one batch of mix for all your planting needs instead of making two different mixes.
Difference in texture
Seed starting mixes are also much finer in texture than potting soil. Since it does contain ingredients such as peat moss, coconut coir, perlite, and vermiculite, it is much lighter as well. And also, the fact that it doesn’t contain natural soil makes it even more lightweight.
Seed starting mixes are also lightweight and specifically designed not to weigh down your seeds as they germinate. On the other hand, potting soil is denser and coarser in texture but generally contains compost or field soil along with other ingredients like peat moss and vermiculite. It normally contains some type of fertilizer but not in all cases.
It is often challenging to understand the differences between seed starting mixes and potting soil. Unfortunately, the labeling on packages does not help the matter. Some companies use the term soilless mix to describe a seed starting mix.
So the only true way to understand these items is to read the ingredient list. So it is always a good idea to know the ingredients included in seed starting mixes as well as the ingredients contained in potting soil.
As a rule of thumb, if it contains no compost, sand, or field soil, then it is a seed starting mix. On the other hand, if it does contain compost, field soil, or sand, then it’s definitely potting soil
Lots of people just starting out in the gardening field often wonder whether seed starting mixes are necessary. Well, the short answer is no, it’s not necessary. However, plants will be grateful for it.
Since seed starting mixes are designed to offer the perfect growing environment for seeds, it creates a thriving environment for your seeds to germinate and thrive. Using soil is also acceptable in most cases. However, the potting soil won’t be suitable if it contains high levels of fertilizer, topsoil, or sand.
Garden soil is a convenient option since it is readily available, and it’s quite confusing to learn about all the different types of soils out there. However, garden soil to start your seeds is never a good idea. This is because it’s too heavy and may contain weed seeds, pests, and other diseases.
Organic or natural
Organic options are best for growing because they don’t contain ingredients that could be harmful to the environment. However, there’s not much that you can grasp when you read an organic label over exactly what it means in terms of potting soil and seed starting mixes.
Lots of companies use the “organic” label on their products, but these growing mediums are not approved for organic gardening.
The “natural” labeling, unfortunately, means even less than the organic label. Most potting soils and seed starting mixes are already natural, and this is because they are made up of ingredients from the earth such as sphagnum moss, perlite, and soil.
All potting soil and soilless mixes should be labeled natural by default.
Making the right choice
There are literally hundreds of options out there, all claiming to be the best. Seed starting and potting soil mixes are available in a wide range of sizes and claims, and sorting through them can be time-consuming and ultimately overwhelming.
But being an informed buyer is one of the best ways to get the right mix to grow your plants. And contrary to popular belief, the most expensive ones aren’t necessarily the best.
Likewise, making the right choice is important as the wrong product may negatively affect the growth of your seeds, forcing you to start over. This is never fun for any gardener, whether you are a beginner or seasoned one, so the best thing to do is to start off correctly, saving you time and heartache on failed gardening attempts.
How do you make a seed starter?
When looking for a seed starting mix or potting soil online, you’ll usually find about ten or more different recipes. However, there are always variations to what you find online, and it can sometimes work best for you.
So feel free to modify those as you wish with different ingredients and see what works best for your seeds. It can be useful for both seed starting and growing in containers, and the mix will last you for many years. So this is what you need to make your own seed starting mix:
- 4 parts sphagnum peat moss
- 1 part vermiculite
- 1 part compost
- 1 part perlite
- 1 part worm castings
Here’s a little description of what each ingredient will bring to your seed starting mix.
Peat moss: This is an organic material that holds water well and can be compared to the way a sponge holds water. It holds nutrients in the soil instead of letting them leak out and also has a good soil structure.
Vermiculite: This is a group of minerals that increases water and nutrient retention and helps plants absorb nutrients such as potassium, ammonium, calcium, and magnesium.
Perlite: This is actually a volcanic glass that is heated up and popped like popcorn. It results in a material whose main purpose is great soil aeration.
Compost: Compost is a good source of organic matter that slowly provides nutrients to plants. It holds water well and does not compact easily since it is light. You can make your own compost from shredded leaves, glass clippings, used coffee grounds from a local coffee shop as well as other clippings from your very own garden. In the event that you cannot make your own compost, you can purchase it at a garden store in bulk.
Worm castings: Worm castings are often referred to as black gold by gardeners. While they provide a great source of nutrients for the plants, they can also be made for free. If you cannot easily access worm castings or compost, buy it and add granular fertilizers to the mix.
Steps for making seed starting mix
You want to start by gathering up all your supplies and have them on hand. You can use a wheelbarrow to mix all the ingredients together, and this can also be done on a tarp, depending on how much of the mix is needed. In order to measure the “parts” of the recipe, use a bowl from the kitchen or any container will work fine.
A close water source is also necessary. So get a large pitcher of water or a large bucket will also suffice. If it’s springtime or summertime, you can simply use a hose to make it easier because you’ll need a lot of water to moisten the mix.
This is an optional step but necessary for seed starting. A coarse mix with a lot of big chunks of material is less than ideal for starting seeds. So this is why you need to sift the compost and worm castings.
You can find this ahead of time and store it in 5-gallon buckets. In order to sift the material, use a simple square screen made from some scrap wood with a one quarter inch metal screen that you can purchase from any hardware store.
The sifter should be approximately the same size as the wheelbarrow or other container that you are using to do the mix. Take the larger material sifted out and place it back into the compost and take the sifted material and keep it aside.
In step three, you’ll simply need to add the ingredients above back into the wheelbarrow using the bowl as the measuring device.
Scoop out four bowls of peat moss, one bowl of vermiculite, one bowl of perlite, and one part of compost and worm castings. If you are sensitive to breathing in this material, we suggest that you use a mask. It’s also quite a dry mix and creates a lot of dust, especially outside with the wind.
In the step, you need to water the mix thoroughly. It will take more water than you may think because the mixture is extremely good at retaining water. So use the pitcher or hose and water it down a bit. Then start mixing all the materials together using your hands.
Next, you can add more water and continue to mix and add water until the entire mixture has the right amount of moisture. It should be as wet as a wrung-out sponge.
If you want to know if you have the right texture or the right amount of water in your mix, just scoop up a handful and squeeze it; if one or two drops of water drip out, then you have the right amount of moisture in the mix.
You may choose to use this mixture immediately after making it. For seed starting, you can fill the seed trays and then plant the seeds. So for seed starts, use the starting mixture so you never have to fertilize your plants before going into the ground.
You can also use the same mixture when transplanting small seedlings into larger pots when the time is right. So it’s not really necessary to have different mixtures or to buy anything else in store for the different stages of your plant’s life. You can simply use this potting soil for container gardening as well as before transplanting them.
Container gardening may, however, require additional fertilizer, but this potting soil should give your plants a great start. When the time is right, you can add a very small amount of granular organic fertilizer to some of the containers as well as a good nitrogen source such as fish emulsion or blood meal.
The rest of the soil can be used for additional seeds or containers. Simply store them in 5-gallon buckets and keep them in your storeroom or garage. You may choose to use the lid on the buckets; however, it’s not necessary. If the mix does dry out, it’ll just need to be watered down again.
Can you start seeds in the potting mix?
Potting soil may be used to start seeds; however, they tend to have a coarser texture and may contain compost, field soil, or composted manure along with other components or ingredients that may not be suitable for starting seeds. This is an inconvenience, and very few seeds will be viable if the soil has been pasteurized.
If you’re looking to save time and money, then DIY potting soil and seed starting mixes can really help you out.
This is especially when large quantities are required. Both of these options can be quite pricey to purchase by the bag and may not go very far, especially if there are many containers to be filled.
So a more affordable option is to create your own seed starting mixes, and the bonus is that you don’t have to worry about purchasing additional fertilizer for seed starts.
Lindsey Hyland grew up in Arizona where she studied at the University of Arizona’s Controlled Environment Agriculture Center. She furthered her gardening education by working on various organic farms in both rural and urban settings. She started UrbanOrganicYield.com to discuss gardening tips and tactics. Whether it’s succulents and houseplants or vegetables and herbs, growing and caring for just about anything in a garden gets her excited. She is especially passionate about sustainable ways to better run small-scale farms, hydroponics, urban farming, and indoor gardening.