Starting Seeds using Peat Pellets

I spent most of winter eagerly anticipating the arrival of gardening season. I love being able to snip herbs and pick veggies as I'm cooking, so I look forward to having a garden every Spring. When my Korean perilla started to produce seeds last year, I decided to harvest the seeds to plant. Since then, I’ve kept a little jar in my fridge just waiting for a chance to germinate the seeds. More than anything, I was curious to see if the seeds were actually viable and able to grow. I decided to try starting the seeds using peat pellets. I was given a supply and figured this would be a good chance to put them to the test and try to germinate my own seeds.

What are peat pellets?

Peat pellets are small, compressed discs made from peat moss, a natural organic material derived from decomposed plant matter found in wetlands. Commonly used in gardening as a seed-starting medium, peat moss is also used as a fertilizer so the pellets naturally contain a lot of nutrients. They're typically encased in a light mesh netting which some people prefer to remove before transplanting. They are biodegradable so it's not absolutely necessary, but it's simple to remove and easier to plant.

The ones I have are small—about 1-½” round and only ½” tall—but when hydrated, expand to 3 times their original height. They are a mess-free and easy way to start seeds indoors.

A step-by-step guide on starting seeds using peat pellets

Step 1: how many seeds per peat pellet?

To start, decide how many pellets you need for your seeds. I like to place two seeds per pellet in case one fails to germinate. The peat pellets I used were stored in a plastic zip lock bag and were at least a year or two old, so I decided to soak them in water. Newer pellets, however, can go directly in seed trays and can be hydrated by pouring luke-warm water directly over them. They should expand in 10 to 15 minutes.

Step 2

Tear the netting on top and scrape a small, shallow indentation using a toothpick to create a well. After carefully placing the seeds, put a light coating of the peat to cover the seeds. Place each pod in a seed tray. These are made specifically for germinating seeds in peat pellets. Cover the tray with the plastic lid.

Step 3

Always label your seeds! You can create cute labels using toothpicks and some paper to make little flags. I currently have two trays of seeds germinating with various herbs in one and my perilla seeds in another, so it's important to label your seeds so you remember what you planted.

Step 4

At this point the seed tray needs to go in a warm area without direct sunlight. Too much sun can also inhibit the seeds from germinating, so a warm, but shaded place in your home is ideal. The clear, transparent dome covering the tray allows light to enter while keeping humidity in. I put a small amount of water in the bottom of the tray to keep the humidity at about 60%. You can periodically check to see if the pellets are still damp, but only water them if they are dry to the touch.

Step 5

Move the trays to a sunny spot, uncovered, once the seeds have sprouted. If some of the pellets don't show signs of germination, only move the sprouted seeds together in the sun. It's handy to have multiple trays for this purpose. If multiple plants have sprouted in a pellet like mine has in the photo below, you can thin them down so that you end up with one strong seedling plant. I'm curious to see if this step is necessary so I've left some pellets with multiple plants to compare.

My germination results and when to transplant

I started my perilla seeds in late February when we had a spell of warm weather. Spring felt like it was imminent, but it got cooler again as it often does this time of year. As of mid-April, the cold weather hasn’t quite let up. What does this mean for my seeds? As you know, seeds need the proper temperature to germinate properly.

These conditions were not met in my apartment so I had a very poor germination rate. I believe only four seeds out of 25 sprouted. It could be that the peat pellets were old or the trays were not warm enough. I also wonder if I started the process too early. I had far more success using the paper towel method for my perilla seeds, but greater success using peat pellets with other seeds at a rate of 60% germination.

I'm still trying to figure out when to transplant my seedlings into bigger 4" pots or directly in soil outdoors. I'm looking for a second set of leaves or roots pushing through the netting of the pellets as signs that it's time. This is my first year germinating seeds for my balcony garden so I'm learning as I go, but I do find that starting seeds using peat pellets is really simple and easy. I'll report back as the growing season progresses!