Starting seeds each spring is one of the first things to get us exciting for this year’s garden. Getting your hands dirty and watching the seeds emerge from the soil means the snow is melting, the ground is thawing and soon it will be time to plant. Starting healthy seeds starts with finding the best seed starting mix and helps you avoid problems from the start.
Seed starting mix or soil is not actually soil, but a carefully crafted mix of materials to help the plants get their best start. Most of the seed starting mixes on the market used to include Sphagnum moss, and not have coconut coir which is a more sustainable option. The best seed starting mix is smooth with no large clumps, fresh, and sterile to avoid unwanted weeds and infections.
If you are looking for more seed starting supplies, check out:
- 5 Best Grow Lights for Seedlings and For Seed Starting
- Find the Best Seed Starter Kit – 5 Great Options
Quick Look at the Best Seed Starting Mix
Below you can see our top 5 suggestions the best seed starting mix for your flowers and vegetables. You can find most of these products online or locally. Scroll down to learn more about what to look for is a seed starting mix and more details on the out favorite seed starting soil.
Excellent all around organic seed starting mix.
This is agreat product that also comes with potting soil.
This is an excellent seed starter and what we use for our seeds.
These pelleted seed starters are easy to use
Just add water and you've got a healthy seed starting soil.
What to Look for in a Seed Starting Mix
Getting the best seed starting mix helps to eliminate problems before they start and gives your seeds the best chance of success. Below are a few things to look for when selecting seed starter.
The first thing to look at is whether the seed starting mix is organic. We prefer organic soil starter as it avoid the use of chemicals. This is especially important if you are using the soil to start seeds for fruit or vegetables that you might be consuming. Most seed starting mixes list very clearly is the product is organic, but you can also check the ingredients list. You should look specifically for the label OMRI-listed. This means that the product has been listed as organic by a third party non profit organization – Organic Materials Review Institute.
Amount of Mix in the Bag
The amount of mix or soil in the bag is important, especially if you are ordering the soil online. Many of the bags that seem like a good price are simply smaller and you will need to buy a lot to start your own seeds. Seed starting mix typically comes in volumes of 4-12 quarts.
Two of the products on this list expand when you add water, so the size of the package can be deceiving. You can expect the pellets and soil block to expand dramatically.
In addition to selecting organic seed starter, you also want to consider sustainability. Peat moss is a common ingredient in many mixes, but it is environmentally problematic for several reasons. The biggest issue is that it is a finite resource as it takes a long time to regenerate. In addition, peat bogs are fragile ecosystems. There is some work to create peat moss in a sustainable way, but we’re not quite there yet on a large scale.
An excellent alternative to peat moss is coconut coir. This is a sustainable product and is found in many seed starting mixes.
You can read more about Peat Moss here
Not all seed starting mix is created equal. This means that some soil is designed to start flower seeds, while other mixes do a better job with flowers or even succulents. Part of the difference is the type of nutrients, while other differences include how well the soil drains. Make sure to read the bag carefully so you get the right mix for your purpose.
7 Best Seed Starting Mix Choices
This is an excellent all around choice for the best seed starter mix. This mix is consistently excellent and we’ve had excellent results. We’ve also used this mix to root cuttings with success. It’s also organic, meaning that your seedlings start off healthy and organic from the start.
The only negative with this mix is that it has sphagnum moss which is not a sustainable ingredient.
This is a 2 for 1 deal as you get a bag of seed starter and a bag of potting soil. The seed starter is perfectly balanced and is an excellent medium for starting seeds.
We’ve used this seed starter twice with excellent results.
This mixture is readily available in most places in New England where we live and it’s out go to seed starter. Made of a well balanced mixture of nutrients and soil, this is a top notch seed starter.
You can find this at some nurseries and plant centers, or order it online.
Pelleted seed starting soil is a great option – especially if you are only starting a few seeds and want an easy method without all the mess. These pellets are then planted directly into the garden minimizing root disturbances. To use pellets simply add water. These pellets are made from sustainable coco coir fiber and are organic.
This seed starting block is a great option if you are ordering online as it’s compact. To use this soil, simply add water and give the block time to absorb. This seed starting soil is also organic and uses sustainable coconut coir.
How to Start Seeds
Starting seeds is a great way to kick start your garden. You can start seeds indoors during the late winter and spring so you have healthy seedlings when it’s time to plant outside.
To start seeds indoors you need just a few supplies and you can see a list of the supplies below. It is possible to start seeds without some of the more expensive supplies (like grow lights) but if you plan to grow seeds every year, it’s worth investing in some good equipment. You can also use supplies that you have around the house to start seeds if you don’t want to invest up front and build up your equipment over time. At a minimum, you need seed trays, seeds, and seed starting mix.
If you are looking for an easy way to get started you can buy a seed starting kit.
Seed Starting Supplies
- Seed trays, drip tray and cover – see more on selecting the best seed starting trays
- The best seed starting mix (choose from above)
- Grow lights (see our suggestions for the best grow lights)
- Heat Mat
- Spray bottle/watering can
- Plant labels
Once you’ve gathered your supplies, you’re ready to get started. Below you can find the steps for starting seeds:
- Look at your seed packets. The seed packet will list when that crop should be started based on the number of days before the last frost. You will need to determine your last frost date (you can do this on many sites online like this one). Use this information to come up with a date to start your seeds. You will likely need to start seeds at several times as some seeds need just a few weeks and others need more time.
- Fill your see trays with one of the best seed starting mix options above. Gently pat down each cell so there are no air pockets. Make sure the seed starting soil is moist – you will likely need to add water and mix it into your soil before you add it to the seed trays.
- Sow your seeds following the directions on the packet. In general seeds should be placed just below the surface. Small seeds can be just covered with soil, while large seeds can be pushed slightly down into each seed tray cell.
- Cover lightly with soil and water/mist. Place your seed trays in the drip tray and cover. Place on top of a heat mat (if you don’t have a heat mat, place somewhere warm to aid in germination.
- Keep seedling trays moist. Once seeds have germinated, they need sunlight for 12-16 hours a day. Use grow lights keeping them just a few inches above the seedlings.
- Provide your seedlings with light and water until your seedlings are healthy and it’s time to plant them outside. Before you plant them outside, make sure you harden them off before you transplant them into the garden.
- Plant your seedlings into the garden being as careful as you can not to disturb their roots.
See more about How to Start Vegetable Seeds Indoors
Common Seed Starting Problems
Most of the common seed starting problems occur when you either don’t start with the right equipment, or don’t maintain your seedlings. We’ve made all the mistakes (like using garden soil instead of one of the best seed starting mix options above), not using lights and overlooking planting times.
Common Questions About the Best Seed Starting Mix
Do you really need to use seed starting mix?
To get the best results you should plan to start your seeds early with one of the best seed starting mixes above. This gives your seeds extra time to grow and the best seed starting mix ensures they get off to a good start. There are some seeds (like carrots and squash that don’t like having their roots disturbed and should be planted directly into the ground.
Can you just use garden soil to start seeds?
Starting your seeds with garden soil may seem like the best solution – it’s easy, cheap, and you likely already have some outside in your garden. There are several problems with starting your seeds with garden soil.
The first problem is that there are likely weed seeds in the soil. This means that your new plant will compete with these weed seeds for water and nutrients. While you can remove the weeds, this disrupts the tiny new roots of your seedling. The second problem is that garden soil tends to become compacted in the seed tray cells making it difficult for the seeds to germinate. The final problem is that the soil from your garden is full of microbes both good and bad – while this might be ok outside in the garden, it can cause real problems in the house.
It is possible to make your own seed starting soil with just a few ingredients. Learn more about making your own seed starting mix.