Seed Starting Pots and Holders

When starting your seeds indoors, timing them to be planted outdoors at the perfect size can be tricky. Unsettled weather and short growing seasons can make it advantageous to pot up your seedlings before they make a move to their final home. Being left in cell trays or pots that are too small will stunt the growth of your plants. They will run out of soil space and may become root bound before you can transplant your seedling outside.

How to use seed starting pots

Our 2.5” seed starter pots can be directly planted into or used as an up-pot for seedlings grown in cell trays. Many growers will start with this size and then either up-pot into our 3" pots or  5” pots or directly transplant the plant into their outdoor growing space. Check out this helpful video, How to Repot Tomatoes for Bigger Better Plants | Up Potting Seedlings, where we show you how to up pot from the 2.5” seed starter pots into the 5” pots.

Do I Need Inserts for My Starter Pots?

No. These are optional components, but they are handy. The 2.5” and the 5” can be purchased with or without inserts designed to fit the 1020 tray. These inserts not only make bottom-watering easier, but they also make transport easier. We recommend pairing the 2.5” pots with these 32 cell inserts with a shallow 1020 tray without holes for the best fit. If you are not using the insert, 1020 deep is a great choice, too. The 5” pots can be bought separately or with an insert and paired with 1020 deep without holes. 

Why plant seeds in small pots?

 Using smaller containers to start seeds has a few notable advantages. 

• It saves space, soil, and water while waiting for seeds to germinate. 
• It allows you to plant multiples of all your seeds and select only the strongest starts to pot up.  
• Individual pots can be moved around for better light and airflow.
• Pots can be moved into the hardening off stage as each plant is ready rather than moving an entire cell plug tray.

Can I start seeds in bigger pots? 

The short answer is, yes, you could, but why would you? Larger pots require more soil or growing media to fill, more space, and more attention to keep moisture levels even. Starting seeds in large pots also can cause problems if not all of your seeds germinate. Why take up all that space in your seed starting area with containers that don't even have a viable plant in them yet? It is more cost and space effective to start in smaller containers and pot up as needed. 

The one exception to this statement is for plants that despise being transplanted. Some garden plants like cucumbers and squash do not like their roots disturbed and should be fiddled with as little as possible before transplanting outside. Many flowers like zinnias and calendula also do not appreciate having their roots disturbed. Root disturbance can even cause multi-layer petal forms of zinnias to revert to the single petal form.  

What Pot Size Should I Use?

What is the best size pot for planting tomato seeds?

Our 2.5-inch seed starter pots are a perfect size for plants like tomatoes that must be kept protected until outside temperatures are consistently above freezing. They can be used for starting tomato seeds instead of a cell tray. Thes pots also work great for starting zinnias 3-4 weeks before your last frost date. They can easily be bottom watered using the 32-cell tray with a shallow 1020 tray to hold water. 

Because tomatoes are typically started indoors 6-8 weeks before your last frost date they will need more space than most seedlings to grow while waiting for their final spot in the garden. Tomatoes can be easily started in a 72-cell tray for saving space but they will need to be transplanted into a larger pot fairly quickly. 

How to know when your seedlings need to be potted up.

If starting seedlings in a cell tray, you will need to repot or transplant them after 6-8 weeks to prevent root binding and stunted growth. If planting into a 2.5” pot you will need to transplant them right before they outgrow their container. Check the underside of the pot and notice the root growth, this is an indication that your plant needs more room to grow. Squeeze the container- if it doesn’t have much give, it's time to repot it into a larger container. If your plant has gotten leggy, you can easily bury some of that stem at transplant time.

The best way to water seed starting pots. 

Our favorite method of watering seedlings is bottom-watering. We recommend using either shallow or deep 1020 flats without holes for this process. Interested in learning more about seed starting? Check out Seed Starting 101: Starting Seeds Indoors for Your Garden.