Gardening: How to Build a Germination Station

March 10, 2023


Germination StationIn colder climates or seasons where weather patterns are erratic, a germination station and indoor growing for the early stages of plants are essential for a good yield.  Most people don’t consider an indoor sprouting or germination station because they feel it’s too expensive or difficult to set up.  In this blog, we will show you how wrong those assumptions are by building a germination station for around a hundred or two hundred dollars, planting more seedlings than we could possibly plant in my space, alerting you to a few potential problems, and we’ll tell you the real story about how much electricity these systems use. Let’s get growing…


Soil Blocks and Seed TraysWhat you plant your seeds in will determine how well they germinate and how easily they transfer from your station to the garden.  Here we will be using a hexagonal seed tray with 72 grow areas and soil blocks that we will show you how to make.  We picked this one up for around $5.00 at the local hardware store, and making a basic one out of soil pods and a clear, hinged take-out container is also an option.  Each has advantages and disadvantages, which come down to time and convenience.  First, the seed trays are made for convenience.  This hexagonal structure is superior to square or round, as the roots find the walls and shoot downward rather than spiraling around.  Eliminating circular roots creates a better root structure for your plant when placed in its final garden spot because the roots will spread out more easily and will be less in a clump.  

The problem with these is that seeds germinate and sprout at different rates.  These okra, for instance, are already touching the top of the container before my peppers have even sprouted.  The deeper grow cell also encourages the roots to shoot straight down rather than out, which is a problem over soil blocks that we will detail in a comparison later in this blog.  We will need to transplant them by squeezing the bottom of the pod and carefully removing the seedlings to a slightly larger pot.  For that, we can use plastic cups, small 4-6″ pots, or paper fiber-based pots.  If you use cups, ensure a hole in the bottom for excess water to drain out.  The advantage to the paper pots is they will deteriorate in the garden, so to plant, we only need to remove the bottom and put them in the garden.

We found these self-contained systems for as low as $1.99.  This one would allow me to start a dozen plants, which makes it ideal for the small-space gardener.  The smaller setups would also allow us to put seeds of all the same kind in the container, eliminating the problem of faster shoots.  These self-contained systems also come with a clear lid to keep the humidity in the growing area but allow your grow lights to shine through enough to reduce mold and algae problems.  That’s what you want.  If you want to avoid mixing soil, and you can plant in successively larger pots to prevent circular roots, you can use soil pods and a clear, hinged take-out container with similar results.  The advantage of this style is the retention of humidity.

The other option is soil blocks.  This is more hands-on, but it’s the cheapest route with the least amount of waste in the long run.  For this, you need a soil block maker.  We picked this one up on clearance for around $7.00.  It allows me to make small, 1-inch blocks.  These come in 2″ 4″ and even 6″ models and average over $20, but they will last you a lifetime of planting.  The advantage of soil blocks is that a well-made one will hold moisture at its core where the seedlings need it.  Because the outside is exposed to the air and roots die off when exposed to air, the soil block air prunes the root structure on the walls.  This helps to keep the plant from rapidly growing tall before it can adequately support itself.  You end up with hardier plants.

The key to a good soil block is the mix, and we will put my recipe in the comments below.  Typically, it’s 1 part peat moss or coco coir, which is coconut fiber, one part compost or garden soil, and 1/2 part vermiculite, perlite, pumice stone, or sand.  The blocks get more complex from there with exotic ingredients like green sand, colloidal phosphate, basalt rock powder, worm castings, and feather meal, but we find this mix works the best because the ingredients can all be found at low cost.  For our mix, we’ll use one half-measuring container of peat moss.  Instead of compost for the organic nutrients, we are using a 6 lb. bag of worm castings, proportionally the same amount as the peat moss.  You could use compost for this part, as what we are doing is putting organic nutrients in the soil.  Then, add the same amount of garden soil. The garden soil tends to be very woody, so lean toward the finer mixes, as these will absorb and retain water better and clump up as needed.  Some garden mixes also contain fertilizer or perlite in the mix.  These will both help your new plants, one providing nutrients and the other allowing the roots to grow better.

Mix this thoroughly together with your hands.  Finally, I will put in 1 scoop of generic plant food, the same as we would use with a water bucket.  This will make sure that I have the essential nutrients for my plants.  I pull out a little of the dry mix before adding water in case we accidentally add too much water.  In that case, we can add a few handfuls of our dry ingredients until we get the perfect mix consistency.  Our final ingredient is a couple of handfuls of perlite and sand to help with soil aeration.

Add water slowly and mix until all the water is fully absorbed.  Continue to add water and mix until you have a consistency in that you can squeeze water out in your hand, but the clump stays together when you toss it between your hands.  Think of it like making snowballs.  You want the balls to keep their form, not explode apart.  The surface will have a little jiggle, and you should have no pooling water.  The clumpiness is what you want.  If it keeps its form when you toss it between your hands, but it also comes apart when you break it up, it’s perfect.  Next, you load the soil blocker.  We really pack it in there and allow the excess water to squeeze out.  These blocks have to keep their form, and we’re not afraid of over-packing because of the mix we just made.  You can load the soil blocker by rocking it in the mix, but we also pack it in, then you can just push the plunger handle down, and you have your soil blocks.  In one sitting, we can easily make about 100.  Leave them in the sun for a few hours to harden up.  You can always remoisten them with a mist, and the core will retain water.

Of course, if you don’t want to mess with any of that, you can purchase pre-made Expanding Seed Starting Soil Pods.  You simply have to soak the pods and then plant your seed.  The two drawbacks are that these sometimes lack nutrients and they are more costly.  You can get around the nutrient part by soaking them in a little compost tea or light plant food water or making sure they are organic, so you know they have organic materials in them to break down and provide nutrients.  We will link to the ones we have used successfully in the past in the section below.


Hexagonal Seed TrayBetween the two methods, we found the soil block was the best.  The hexagonal planter resulted in my Okra sprouts getting too long and spindly without well-developed roots for stability.  The seedlings reacted to their grow container by shooting a root down instead of out in every direction.  The soil block had solid roots that branched out.  Here’s a side-by-side comparison.  The one with the more tendrils was grown in a soil block.  The other was in the hexagon planter.   We had no choice but to transplant the okra because our other plants, like peppers, were still barely sprouting.  We also found that the germination rate with the same soil and same heating pads was much more significant with soil blocks.  When we transplanted the okra into small pots, we were  able to replant other seeds immediately, and that was convenient.

Honestly, moving forward, we will probably only use soil blocks. They worked so well.  The exception would be if we were to plant 72 of the same plant, so the germination rate was more consistent, and we could really let the roots establish with the lid off the germination container.  It’s easier to move outside to harden plants off, as well.  The soil blocks take some time to make and more work, but they’re far superior, in my opinion.  The root structure is denser and branches out.  This provides better stability to the small plant and increases the likelihood of the plant surviving.


Germination StationsThese used to be expensive setups, but the price has come down.  We’ll list all the parts and provide links in the section below.  First, you need a wire shelf.   These range in price, and you may already have one.  You want to be able to create at least two feet of space between shelves, and you want to be able to run your wires through the shelves.  Those are the only two requirements.  For our lights, we got four bulbs on clearance at my local hardware store for $1.99 each, and we got a larger one we obtained for around $14.  These range in price from about $8 for bulbs to $70 or more for large strips and bars.  We constantly find these on sale, so it pays to shop around.  People frequently use these grow lights in terrariums and vivariums.  LED strips with an adjustable light spectrum and intensity have dropped in price in recent years, partly because of terrariums.  These provide even greater light in a wider area with very little energy consumption.

For our bulbs, we are going to use hanging light sockets with cords.  This will allow us to adjust the bulb’s height over the plants and to turn them off an on separately.  The light will provide the plant with what it needs for photosynthesis, warm it slightly, and reduce algae, moss, and fungal growth.  Our bulbs are called full-spectrum, providing a wide range of the wavelengths of light needed for plants.  As you explore grow lights, you will see they get progressively more specialized, allowing you to adjust the wavelength.  Violet or purple light has a shorter wavelength and higher energy. It is considered effective as a light source to facilitate the growth and development of a plant’s leafy vegetation.  For our purposes of basic germination and not a whole indoor growth operation, basic full-spectrum grow light bulbs are perfect.

Finally, you will need a power strip to connect everything up to and these seedling warming mats.  Seeds each have a preferred temperature they want the soil to be before they germinate and sprout, so you have to warm the soil.  If this setup is in winter in your garage, nothing will probably sprout without these.  We will use one each for the two different trays.

If your concern is electricity consumption, don’t be worried.  Our entire setup, that’s five lights, two heat mats, and a fan only consumes just around 130 watts.  So, this whole setup uses about the same electricity as one bright lamp bulb.

We constructed the shelf with a 2-foot or more growing area space, and we used zip ties and tape to secure wires and keep the system neat.  Wires are easily threaded through the wire shelves and secured with simple twist ties. This will allow us to individually turn them off and on and adjust their heights as we need to.  We will wrap two sides with aluminum foil to reflect and concentrate the light and reduce drafts.  This is easily fastened down with a little crinkling and then tape.


Labeling PlantsTwo potential problems are gnats and failing to keep track of plants.  We use yellow sticky traps for the gnats.  These are natural in most compost and any soil that has been exposed to the outside for any length of time.  They are harmless but very annoying.  Too many can cause problems with your plants.  We find the sticky traps work quite effectively.  They’re an inexpensive solution that replaces costly and potentially toxic chemical solutions.

The second problem is failing to label your plants.  Most pepper sprouts all look the same, so you have to label them.  The same is true for young tomato plants.  You have to label them to avoid mixing them up.  When you do transfer to the garden, you run the risk of planting them too close together or planting too many of one type and not enough of another.  Do yourself a favor and label each of your plants from the moment the seed drops into the pot you plan to move it in.  Then, transfer the label marker to the plant in your garden.


Transferrng To Small PotsNext, you will want to plant one to two seeds per block and make sure that your plant rows are all marked.  Two seeds will allow you to thin them out later but will provide a greater germination rate.  Water the soil blocks at least twice per day so conditions are right for sprouting.  The enclosed structures may not need any watering at all because of their ability to retain moisture and humidity.  Cover soil blocks with clear plastic wrap in the early days to help seal in moisture.  Seeds germinate at different rates.  Typically after the second set of leaves appears on your plants, they are ready to be transplanted into small pots.  There is no problem with waiting longer, and it is best to wait as long as possible.  If the plants are a little crowded, that’s okay.  They are still developing a solid foundation from which to grow.  You will want to keep your grow lights just a few inches above your plants after removing any plastic humidity barrier.  Keep the soil moist by spraying at least twice per day.  You will also want to incorporate a small fan for a gentle breeze.  Plants breathe just like humans, and the breeze helps with the exchange of air, regulates temperatures, and encourages stalk development.

When the last chance of frost has passed, you can slowly introduce your potted plants to the outside environment.  First, introduce them on a warm day by placing them in the shade for a few hours.  Progressively, increase their time outdoors and sun exposure.  This process is called “hardening off.”  When the plants can survive outdoors with the direct sunlight they require, and the fear of frost has passed, you can leave them outdoors overnight.

Move the pots around your garden area for a few days to ensure the plants appear healthy in their new homes, then transplant them to the soil.  You will be weeks ahead of other gardeners by germinating indoors with a grow station.  Your plants will be healthier and better established than any larger, store-bought variety.  You will also be harvesting well ahead of other gardeners.

So, for around a hundred to two-hundred dollars, depending upon what you have on hand, and with some ingenuity, you can easily set up an indoor grow station.  Use it throughout the season to develop heartier plants for your growing area.  If the weather becomes erratic and unpredictable or a disaster wipes out your garden, you can grow some plants indoors.  You are only limited by your space.



  • 1 part Peat Moss
  • 1 16-ounce bag worm castings
  • 1 part garden soil
  • 2 handfuls perlite
  • 1 handful sand
  • 1 scoop generic plant food




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