Seed Starting: a Comparative Study on Cheap Indoor Methods

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!