I finally bought reusable seed starting trays to replace the flimsy black plastic ones that crack apart after a single season. The new seed starting trays are silicon, can be sanitized in the dishwasher, and come with humidity domes and built in mini grow lights.

You will get efficient and thoughtful service from MARSHINE.

The cost is pretty affordable as well, coming out to about $0.50 cents per plant. I plan to use these for the next 10 years or more, which means they would come out to about $0.05 cents instead!

Jump to:

• My current seed starting setup
• Product details
• Seed starting mixes
• Alternative seed starting options
• Where to buy
• Store your seeds in a binder
• You might also like

My current seed starting setup

I bought these colorful silicon seed starting trays this year - both for fun and function. They sit adorably in the window, making me smile every time I walk by. As a bonus - they are as practical as they are cute.

Update : sadly, the product I bought has been replaced with just the silicon trays, without the humidity dome or lights. You can try these instead, which look to be the same (but less colorful).

Why use silicon seed starting trays

Silicon seed starting trays have recently started popping up and are gaining popularity over the standard paper-thin black plastic trays you find at nurseries. Those plastic trays crack after one use and can get a bit toasty on a seedling heat mat.

The silicon trays are flexible, making it easy to push on the bottom to pop the plant out for transplanting. They can also be placed in the dishwasher for easy sanitizing year after year.

Why these trays

After browsing through all of the silicon seed starting tray options on Amazon and nursery websites, I settled on these trays from Amazon. I think you get a lot for the price and the quality is high.

I bought the 8-pack of silicon trays that each come with a thick plastic bottom, and a tall 4" humidity dome with mini grow lights built in. It also comes with 80 plant tags and a couple mini plastic tools for punching holes in soil or scooping soil. Each tray has 9 cells for a total of 72 cells.

update: the trays I bought have been replaced by the seller with just the trays (no humidity domes or grow lights). You can try these instead.

Product details

I took measurements of the seed starting trays in case you are trying to fit them on a windowsill, a standard tray size, or trying to determine what to use for your seed starting medium.

• Silicon tray is exactly 5" x 5"
• Cell interior is 1.5" x 1.5"
• Silicon tray height: 2.25"
• Plastic tray: 5.75" x 5.75" to edge of lip, and 4.75" x 4.75" across the bottom
• Plastic tray height: 2.75"
• Dome: 4" high
• USB cable to power grow lights: 14" long

The 8-pack of silicon trays comes with 4 USB "double" cables to power the grow lights. Each cable splits into 2 cords and each of those cords is 14" long. I bought a $15 USB power strip to plug them in.

Everything you need for seed starting is listed at the bottom of this post, in one place.

Seed starting mixes

In my experience, the most important factor for successful seed starting is finding the right soil or growing medium. This can make germination easy or near impossible, depending on what you choose. The two easiest seed starting options are Horticubes and OrganiPlugs. Seed starting soil mixes are also a good option.

Seeds need to stay moist in order to germinate. It might seem like you can simply pick any soil and keep it watered, but too much water without drying out invites mold. Mold can stunt or kill the seedlings.

Seed starting soil mixes are formulated to hold moisture, often including perlite or peat, which is a good thing! But I've found soil to be too finicky for seed germination for my liking. It seems too easy to underwater, resulting in poor germination, but overwatering often leads to mold growth on the top. I know other people who have had more luck with soil mixes or soil blocking.

This year I'm trying out OrganiPlugs and they've worked out well so far. They are made of peat and coco coir and feel quite spongy. They stay moist and so far I haven't run into mold problems (and don't expect to).

OrganiPlugs are made to fit into standard seed starting trays. They fit almost perfectly in each cell of the silicon trays I bought - they have just a little bit of wiggle room.

I'm also using Horticubes for herbs this year. They don't fit in the silicon trays, instead they are meant to sit in a large tray then get transplanted shortly after germination.

(All of the products are also listed at the bottom of this post in one place).

Alternative seed starting options

I have a couple other options to suggest if for some reason you don't want to share in the joy of these cute, resusable trays!

Upcycle disposable containers

Empty yogurt, fruit cup, or applesauce containers make great seed starting pots - just be sure to drill a few holes in the bottom. Leftover take-out containers work well as a tray to collect the draining water.

When upcycling containers, you'll likely need to use a seed starting soil mix. If you do this, be sure to check the moisture levels several times a day so it doesn't dry out, or stay too wet.

OrganiPlug pre-filled tray

OrganiPlug offers a 50-cell tray pre-filled with their OrganiPlugs. It doesn't get much easier than that. However, the tray will likely only be usable for 1-2 years as the thin plastic will crack as you remove the plants for transplanting.

Oasis Horticubes

I actually use this seed starting method every year, including this year - Horticubes. They are the most reliable and easiest seed germinating medium. I really can't stress how easy these are to use.

These feel like foam but are made from biodegradable materials that will continuously break down over the course of the year. It's sterile medium so it won't transfer pests or diseases.

Horticubes hold water extremely well and don't mold. Seed germination is easy and all but guaranteed. I never run into problems when using Horticubes.

For more information, please visit cheap seed starting trays.

The downside is they are very small and offer no nutrients. That's fine for germination but they will need to be transplanted to larger containers as soon as their first set to true leaves shows up. If you don't transplant, they just stop growing (I know, because I've done it!)

I use these every year for starting herb seeds where I want a bunch of each type of plant. Once they sprout, I transplant them to a larger tray with soil that I continue to water. When they are ready to be transplanted outdoors, I break apart the roots if they've grown together and set them in their sunny spots!

One note worth mentioning is the sheets that arrive are fragile. They can easily break apart if you aren't careful or if shipping was rough.

Get Horticubes on Amazon or Harris Seeds for a similar price.

Other options

There are a few other options to consider - rockwool, foam plugs, and seed starting soil mixes. I don't think these options are as good as the ones listed above, however.

Rockwool is made from molten rock that is spun into threads to create the product. I used rockwool cubes a while back but stopped when I learned it might be harmful to the lungs.

It's too bad because they are a fantastic medium. They are relatively cheap ($0.10 per cube or less), hold water extremely well, and never mold. Seed germination in these is outstanding.

Some people still use them, and I don't feel like I've found enough credible evidence to confidently advise against using these. I personally don't use them because I prefer to err on the side of caution, and I've found other alternatives.

Foam plugs are another option. They actually work quite well - they hold water, don't mold, and are affordable. But I personally don't use them because they don't compost into the soil, leaving little spongy plugs around.

Seed starting soils are formulated specifically for seed starting. They often contain perlite, peat, and coco coir to hold water. As I mentioned earlier though, I always have trouble with either over watering and getting mold problems, or underwatering, resulting in poor germination.

If you've had luck with seed starting soils in the past, then I see no reason you wouldn't continue to have success. It's a good, affordable option!

Where to buy

Amazon is actually a great place for seed starting supplies. I find their prices are often much lower than online seed websites and even hardware stores. The links in this article are affiliate links, which means I get a small commission if you make a purchase (and a big thanks if you do!). In return, I only recommend products that I personally use and feel good recommending.

Everything you need for seed starting with my silicon tray setup:

• Colorful silicon seed starting trays
• OrganiPlug 100 count
• A USB hub for the grow lights

Alternatives

• OrganiPlug pre-filled tray
• Horticubes (larger) - these are the ones I use
• Horticubes (smaller)
• Black plastic 6-cell nursery packs (thin plastic, 1-2 uses)
• Plastic plant labels

Extras:

Seeds need warmth to germinate, so most people set them on a little heat mat. Once they germinate, remove them from the heat mat and leave them at room temperature.

The heat mats get slightly warmer than room temperature, and the inexpensive ones don't have controls other than being plugged in or not. Mine are all like this and were very inexpensive (small ones are around $15). This 10x20" heat mat will fit the 8 silicon trays (they might hang off the edges a little). I don't have this one in particular because I bought mine over 10 years ago. It has good reviews and looks exactly the same as what I use.

Alternatively, set your seeds on top of your fridge to germinate. It's just warm enough to lend a helping hand instead of a heat mat.

Where to buy seeds

I bought seeds from a dozen vendors last year. In part it was to evaluate vendors since so many people ask me for my favorite sources. But part of it was chasing unique varieties that only one or two vendors sold.

I share a dozen of the best places to buy seeds, from incredibly cheap sources for $2 or less, to fully organic but more expensive. I also have a good source that specializes in each specific climate, including the Pacific Northwest, West Coast, Southwest, Southeast, Midwest, and Northeast.

For information on how to start your seeds, Swanson Nursery has a good tutorial.

Store your seeds in a binder

4-pocket binder sheets fit seed packets perfectly. The smallest pack you can buy seems to be 25-30, which gives you 100-120 pockets. When storing them back-to-back (one faces front, one faces back), you get double the storage for 200-240 seed packets. I bought a 50-pack and it was way too many - oops.

I also bought a 1.5" thick binder which was definitely too small. I would definitely recommend a 3" ring binder, especially if you are storing large seeds like beans, peas, and corn.

You might also like

Seed Starting: a Comparative Study on Cheap Indoor Methods

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If you want to learn more, please visit our website Leak-Proof Seedling Trays.

Introduction: Seed Starting: a Comparative Study on Cheap Indoor Methods

About: I am a landscape designer and advocate for native plant-focused and sustainable landscaping, but in the past I have worked in costume production and clothing alteration. I taught myself to hand-tailor, draft p… More About gtrachel » In this instructable, I will offer instructions for making, and discuss the pros and cons of, 5 cheap methods of starting seeds indoors:

(1) Egg cartons
(2) Toilet paper tubes
(3) Milk cartons
(4) Yogurt cups
(5) Peat pots and coco fiber pots

The seeds that I start using these methods include peas (climbers, like other legumes), tomatoes, peppers, and eggplants (nightshades), corn, basil, thyme, parsley, and marigolds.  Since I live in an area where we can get snow into mid-May, it's important for me to have healthy, well-started seedlings by the time we're frost free so that my plants have enough time to mature and produce veggies.

Step 1: What You Need

Take a look at the various starters I've used and decide which ones best suit your needs.  In addition, you will need:

- seed starter mix: it's not that expensive, and superior to potting soil because it's fine and uniform.
- water: I never use plain tap water, because it's chlorinated.  At the very least, I run it through my Brita.  If you have distilled water, that's the best for watering plants.
- something to mix your dirt and water in (I used the bottom half of a gallon jug)
- a latex glove: optional, but dirt dries your skin out and I don't like that, so I wear a glove on my dirt hand.
- seeds.  I like heirloom seeds and buy them from Tomato Bob's website, where they have varieties on sale for twenty-five cents at times.  But the local hardware store or gardening store sells seeds too, and there ain't no shame in that.

That's it.  Do this outside on a mild day, or be prepared to clean up dirt inside.

Step 2: Egg Cartons

Pros: cool and convenient
Cons: too small
Best for: basil

While it's fun to use egg cartons as seed starters, they are at the bottom of my list for effective options.  Why?  Because the egg-shaped spaces are just too darn small.  However, if you want to give them a try, here's what I've learned.

First, cut the carton in half (separating the bottom from the top).

Prep your starter mix by mixing it with water in your vessel of choice.  It should be good and wet.  The texture and color visibly change as it absorbs water; you want it to be about as wet as it can be without having water sitting in the bottom of the bowl.

Fill the egg cups up as much as you can.  Put your seeds on top.  Add more mix.

Line the top of the carton with plastic (I use produce bags from the grocery store).  Put the top half into the bottom half.  This not only stabilizes the whole apparatus, since the cardboard egg carton gets awfully flexible when it's wet, but also keeps moisture in - that cardboard, if exposed to air, wicks moisture away like you wouldn't believe and sucks the life out of your seedlings in just a day.  The plastic lining is essential.

The second photo shows basil growing in pots and in an egg carton.  The potted basil was planted in those pots and is at least a month older than the sprouts.  I intend to keep it indoors in those pots.  But I also want basil to plant in my garden, and that's why I planted more in the egg carton - so I have plenty of sprouts to put in the ground with my tomatoes.  I had basil - notoriously easy to grow - sprout at 100% in the egg carton.  I also have bell peppers sprouting well, but in my third carton, with a mix of eggplant and sweet Italian peppers, I have about 30% no-shows.  I also suspect the size of the egg cavities limit the growth of my seedlings.

Step 3: Toilet Paper Tubes

Pros: compact and easy to transplant
Cons: molds easily
Best for: tomatoes

The toilet paper tube is a step up from the egg carton.  The first step here is to cut these babies in half, because the full length tube is pretty much guaranteed to develop nasty black mold on the bottom, where moisture collects and can't be reached by little baby plant roots.  Gross, and hungry mold risks overpowering and killing your seedlings.

Half-length tubes, however, work pretty well.  You can see in the photos how much cleaner they are than the tall ones.  You'll need a tray to arrange them in.  If you don't want to shell out five bucks for an alleged "seed starter tray," build something yourself - I used the bottom of a paper grocery bag, stabilized with a Netflix ad I got in the mail, and lined with a plastic grocery bag.

Prep your mix as for egg cartons.  Pack it firmly into the tube with the bottom opening blocked by something (like the table, or the bottom of the mix bowl).  Fill most of the way.  You can fill a little more loosely closer to the top.  Put your seeds on top.  Add more mix.  Arrange in your tray.

TP tubes are not good for anything with big, aggressive roots - like corn or peas.  Those roots will grow right out of the bottom and run rampant in your tray, and you will have to transplant within just a few days (see photo #4).  Tomatoes, however, have little bitty roots that don't stray from their mix, and they seem to like TP tubes quite a bit.  Of the tomatoes in my TP and 2" mini peat pot tray, I had a much better result from seeds planted in the TP tubes.

When you want to transplant from the TP tube into something bigger, here's my preferred method:
(1) Fill your desired vessel halfway with damp potting soil.
(2) Place the tube on top, then fill the space around the tube with soil.
(3) Remove the tube by pushing down gently on the seed mix around your seedling with one hand, and pulling up on the tube with the other.  Go slow.
(4) Add more soil after you've removed the tube.  Water.

I don't like to leave the tube in for two reasons: first, I don't want my plants to have to wait for it to decompose before they can stretch their roots out.  Second, there's usually at least a little bit of moldy fuzz starting to develop at the bottom of the tube, and I want that out of the picture.  It's not difficult to remove the tube.  Just be gentle.

Step 4: Milk Cartons

Pros: tomatoes' first choice award
Cons: no separation of seedlings
Best for: tomatoes

Okay, this was a half-assed thing that I tried, and I couldn't believe how well it worked.  I cut a milk carton in half (the long way), filled it about an inch with prepped mix, laid down my tomato seeds, and covered with more mix.

I had 100% germination and the seedlings from the milk carton were the biggest, fastest, best-developed tomatoes of all.  I thought they would be a nightmare to transplant because they were all growing together and I imagined a major root entanglement, but this was not the case.  The tomatoes came apart easily, I transplanted them into 3" and 4" coco fiber pots, and they are doing great.

I don't know why it works so well, but it does.  The second photo shows the milk carton tomatoes transplanted into pots, next to the TP tube and mini-peat tomatoes - they were all planted at the same time.

When you transplant tomatoes, cover the cotyledon leaves (the first leaves, the generic-looking ones) with soil.  I've heard it's good to cover them up to the second set of true leaves, but I transplanted mine before they were that big.  They'll grow roots from the covered part of the stem, and be sturdier plants.

Step 5: Yogurt Cups

Pros: easy, easy, easy
Cons: yogurt is more expensive than eggs or milk
Best for: pretty much everything

Yogurt cups make great seed starters.  They are a good size, they don't rot, and the soft plastic makes it easy to slide your babies out with their roots intact when it's time to transplant.  I love these things.  I don't even poke holes in the bottom (careful not to overwater!).  They hold moisture like pros and everything I've planted in yogurt cups has grown well.

I've put zucchini, peppers, parsley, and marigolds in them.  Procedure: prep mix, fill, plant, and cover.
The first picture shoes marigolds up top and bell peppers on the bottom.  The second photo also shows a huge zucchini sprout (which is only a few days old, while everything else is at least two weeks old) and some parsley as well.

Step 6: Peat and Coco Pots

Pros: roomy, no removal necessary for transplanting
Cons: $$
Best for: big seedlings - legumes, corn

Okay, these are the only starter pots that you actually have to purchase as such, but they are worth it in some cases.

This may seem obvious, but if you plant a big seed, you can expect a big seedling.  In that case, forget about egg cartons and TP tubes.  For huge seeds like peas, beans, corn, and zucchini, go straight to a 4" or 5" peat or coco pot.  Otherwise you'll have to transplant them right away, and a lot of these guys don't like that.  I had at least one healthy pea shoot die on me after transplanting to a larger pot.  So skip that and start big.

I've also used coco pots to step up my tomato seedlings, particularly the ones from the milk carton (second photo).  Everything that needs to be transplanted from its original starter pot will go into one of these, because they've only got another two weeks indoors before they start the transition to the outside.

I'm now planting my peas and corn together.  Why?  Because corn is tall and thin and likes lots of nitrogen, and peas climb and deposit nitrogen in the soil as they grow.  Beans do, as well (it's a legume family trait).  It's a match made in Native American farming techniques heaven.

Prep your mix.  I fill the bottom third or half of the pot with potting soil, and then put seed starter mix on top of that.  Put your seeds on top.  Big seeds tend to prefer to be buried deeper, an inch or so - refer to your packet.  Put mix on top.

A note: I can't recommend the 2" mini peat pots, because they were outperformed in sprouting tomato seedlings by both of the other container types I used with tomatoes.  I conclude that the large ones are useful for large seeds, but for small seeds, other options are preferable.

Step 7: Tips

Here are some things I've learned.

"Thinning" is a heartbreaking experience.  The first seeds I planted were herbs in a pot.  I planted lots of seeds and had to throw most of my seedlings out as they grew.  I now plant seeds individually, one per container (or a couple in a pot, spaced appropriately), and plan for them all to sprout.  If they don't, I can always plant a new seed.  But most seeds sprout.

Covering seedling trays with plastic is not something I do, because I don't have plastic wrap lying around.  I'm attentive to the soil moisture and haven't had any problems.  Seed starter mix holds water particularly well (one of the reasons it's worth buying), but do keep in mind that the smaller your container, the more often you'll need to water it.  The mix is also easily compacted by the impact of a stream of water.  I've found that the handiest way to water small containers without disturbing the soil is to make a SEEDLING WATERER as follows:

1 plastic water bottle with lid
something with which to poke a hole in the lid

Poke a hole in the lid.  Fill the bottle with water and put the lid on.  Squirt the water through the hole onto your seedling pot.  No soil disturbance!

I also don't keep my seeds in the dark before they've germinated.  I'm sure people who insist on doing that have a good reason to do so, but I try to keep things simple and so all my guys are on the same table by my south-facing window.  I figure they're under soil, so it's pretty dark down there, and they seem to be doing fine and germinating in the appropriate time frame.  I don't use grow lights - that would be way expensive - but I do turn my seedlings, sometimes more than once a day, and take them outside when the weather is good.

A note about parsley: parsley takes forever to germinate.  So long that, long after the other herbs I had planted the same day were sprouting their first and even second true leaves, I'd yet to see any action from the parsley.  I finally planted something else on top, but the very next day they sprouted, and they continued to sprout for a couple of weeks.  Some seeds just require a lot of patience, and it never hurts to look them up with Google to get some extra info - seed packets can be frustratingly brief.

Finally, keep track of your planting dates by writing them on your seedling pots (in ballpoint or something similar, which doesn't bleed on cardboard, and sharpie on yogurt cups).  You'll want this information for your own reference.  Also write down varieties, especially if you've got seedlings that look similar (all the nightshades look a like at first, and forget telling two kinds of tomatoes apart).  You can never have too much data.

I hope you've enjoyed my instructable and feel inspired to start your own seeds for cheap.  I'm entering the gardening contest, so if you liked it, please give me a good rating and vote for me.  Good luck!