An Experiment with Coleus

Ever since we set up our little Sunglo greenhouse a few years ago, I’ve been trying to find the best way to start plants from seeds.

So early last spring, I conducted a little experiment:  I planted seeds using three different seed starting kits to learn which method worked the best for me.

Comparing seed starting kits
Seedlings planted in three different seed starting kits

With spring just around the corner, this is a good time to share my findings.

The Three Seed Starting Kits I Tried

Disclosure:  Affiliate links are used below.

There are many types of seed starting kits and trays out there, but for this little exercise I used three easily found, affordable Jiffy products.

Since I’d never planted coleus seeds before, I decided to make coleus the subject of my experiment.  I planted them in all three kits.

I planted several types of coleus but mostly the rainbow mix.

The three Jiffy kits I used were:

Seed Starter Greenhouse.


Peat Pot Strip Sheets.


Peat Soil Pellets.

The Pros and Cons of Each

In this post, I won’t go into the mechanics of how to use each kit.  I believe they all came with instructions – which I mostly followed.  I did modify things slightly to suit my greenhouse environment and to address a concern I had about one of the products.

Here is what I learned:

Seed Starter Greenhouse


Seedlings in the plastic chambers of the Seed Starter Greenhouse


  • If treated right, the plastic potting chambers are reusable year after year.
  • Each tray can start 72 seedlings.


  • The chambers are small so my seedlings outgrew them quickly.
  • Transplanting seedlings from the chambers was more difficult and disruptive to plant roots than using either of the other two methods.
  • I had to separately purchase soil to fill the potting chambers.  The seed starter soil I chose didn’t hold together well, and it seemed to dry out too quickly (which of course was my own fault).
  • Probably because of the soil I used, moisture retention in the potting chambers was uneven.
  • The plastic chambers cannot be separated so, unlike the other two methods, it was impossible to share individual seedlings with friends without transplanting them first.

Peat Pots

Seedlings in peat pots


  • Larger chambers meant the plants didn’t outgrow them as quickly as with the seed starter greenhouse.
  • Transplanting was easy and not disruptive to roots.
  • Since the peat pots could be separated, sharing seedlings with friends was easy.


  • This method also required purchasing soil.
  • Although the plastic tray is reusable, the peat pots are not.
  • Moisture retention seemed uneven, again probably due to the soil I used.

Peat Soil Pellets

Seedlings in peat soil pellets


  • Transplanting was easy and didn’t disrupt roots.
  • Similar to the peat pots, sharing individual seedlings with friends was easy.
  • I’ve read other posts to the contrary but, for my little experiment at least,  moisture retention in the soil pellets was far superior to the first two methods.
  • No need to purchase soil separately.  There was no guess work here.  Everything the seeds needed was already in the soil pellet.
  • I saved a little time with this method since I didn’t have to fill potting chambers with soil – although I did have to soak the pellets in water and wait a bit for them to expand to the correct size and moisture level.


  • The pellets are encased in a mesh, and when a seedling is transplanted, the mesh gets buried in the soil along with the pellet.   However, I have read from several sources that the mesh casing doesn’t always break down when buried in the soil.  And sometimes this restricts root growth.  I wondered about this when I was using them.  I just didn’t like the idea of burying that mesh casing.  So my easy fix was to carefully peel off the mesh when I transplanted the seedlings.  The mesh came off easily and, for the most part, the pellets held together after the casing was removed.
  • I found it just a little more time consuming to plant seeds into the pellets versus the other two methods.
  • Maybe I shouldn’t have listed this under cons but, while the plastic tray is reusable, the pellets are not.  However, a bag of replacement pellets is inexpensive and takes the place of the soil that needs to be purchased with the other two methods.

My Personal Favorite

Even with the extra step of removing the mesh casing, I liked the peat soil pellets the best. And I’m finding that they are available in four different sizes, as illustrated by the chart on this page.  So there are options, but now I’ll be careful to pay attention to which size I’m actually buying.

How the Coleus Did

So how did the coleus fare in these three different methods?  In all three seed starting methods, the seeds sprouted consistently.  However, over time, the ones started in the peat pellets did slightly better – and in some cases much better.  This could have everything to do with the poor soil I used in the other two methods.

Eventually, the coleus had to be transplanted into larger pots.  By this time, I had become somewhat attached to them.  Each plant was a little miracle of color and pattern.  The greenhouse looked so cheerful with these pretty babies.

Growing coleus in a Sunglo greenhouse
Coleus and other plants growing in our Sunglo greenhouse

Finally it was time for them to go outside.  Feeling overly protective of my little gems, I didn’t plant them directly into the garden.  I used them in containers.

In hanging baskets.

Coleus in a hanging basket

In numerous clay pots.

Coleus in clay pot

It was fun to group similar foliage colors and patterns – or to combine plants with heavily contrasting foliage.


Some plants stayed small.  These little guys were given tiny pots and paired with larger plants.

Coleus with ornamental grass.
coleus and begonia
Coleus and begonia

Coleus plants do bloom, but the flowers are insignificant.  The real star of the show is the beautiful and varied foliage.  When backlit by the sun, certain plants have leaves that resemble stained glass.

Coleus leaves

To encourage prolific foliage, I pinched them back when I saw flower buds emerging.

I brought the cuttings inside and put them in vases.

coleus is a spectacular alternative to cut flowers

Some of them sprouted roots in the water.  I didn’t try to plant them in soil, but that may have worked as a propagation method.

In my climate, coleus is an annual, meaning that it only lives until the fall frost kills it.  But I read somewhere that coleus plants can be brought indoors in cold weather for protection and placed back outside in spring.  I have a couple of coleus plants from last summer in my greenhouse now.

Soon they will be sharing space with the coleus seeds I just planted.  I’m looking forward to seeing this year’s beauties once they sprout.

Posts on this website are for entertainment only. The little experiment I describe here was completely unscientific.

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2 Replies to “An Experiment with Coleus”

  1. This sounds like so much fun and your plants are growing beautifully! I usually start seeds in individual pots. I should try my hand at one of these seed starter kits to grow even more plants from seeds. Thanks for sharing!

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