If you're like me, you start your garden while there's still snow on the ground. You probably also have plants that never actually go into the ground and stay in your house. Kitchen herbs and so forth are prime examples. Spinach is another favorite, since you can pick young leaves and eat them at just a few weeks from seed.
Rather than buy a lot of pots to put those in, or purchase a bunch of high-dollar planters for seed starting, I like to just collect containers throughout the year and then use them in the early spring to get my garden going. I live in the north-central U.S. (Wyoming), so getting a head start on my garden is important.
Until you start collecting them (I have a shelf in the basement that these end up getting stacked on), you never realize how many plastic containers of various shapes and sizes you end up with over a year's time. Dozens upon dozens if you have a fairly normal lifestyle. Hundreds of thousands if you're a soda addict.
Step 1: Cutting the Bottle to Size
For this demonstration, I've chosen a simple 2-liter soda bottle. The kind that Coke, Pepsi, 7up, and all the rest come in. I've removed the label and rinsed the bottle with soapy water. You can wash it after you've cut it, which is actually easier, if you'd like. It's all the same.
First, take the bottle and select a spot roughly between halfway and 2/3 of the way up the bottle (in height). How high you decide to cut it is up to you, but the deeper your bottom portion is, the more dirt you'll need and the more roots you'll have for transplanting. As a rule of thumb, I cut them in half for seedlings to starters that will be transplanted and deeper if I plan to use it as a semi-permanent growing pot.
Press the bottle fairly flat and cut it with scissors. A knife will work too, but it's easy to slice yourself instead of the bottle, so I prefer scissors. I still have all ten digits on my hands, so that's proof in the puddin'.
Step 2: Holes for Drainage
After you've cut it, wash it if you haven't already done so. The top half can be sent to the recyclers or used as a funnel (these are perfect preserves funnels for jarring jelly, so you know). The bottom half now needs some holes for drainage.
The next photo shows that after it's been done. I was pretty uniform with my pattern, but you can go crazy if you want. Use a hand drill and small bit or an ice pick and hard surfaced table or workbench.
Step 3: Put in Gravel and Soil
Once the holes are in, the second half of the drainage plan goes into effect: gravel. You can use any kind of relatively light gravel--I had this stuff in a bag that was the winter weight for my pickup truck bed. Gravel from a fish tank, your driveway, whatever will work. Just make sure the rocks aren't any larger than your smallest fingernail. About bean sized is right. Layer the bottom lightly, as shown, but not too much. Just enough to cover the bottom and the holes.
Then fill the rest with potting soil. Nutrient-rich stuff can be used for seed starting or regular dirt with some nutrients added can also be used. The soil shown here is out of the bag, which I received in trade for helping a neighbor. I've also made good soil by mixing thirds of nutrient mix and dirt (1/3 mix, 2/3 dirt) in a bucket or wheelbarrow.
Step 4: Planting In, Using, and Enjoying Your Garden Containers!
As you can see from the array on top of our puppy kennel, any plastic container will work great. Big Gulp cups, coffee cans, soda bottles, etc. Even the little half liter bottles work great for seed starters that make for easy transplanting. Just make sure they're plastic, not metal. Metal tends to rust and can affect the plants faster than you'd expect.
The seed bed you can see in that background is the cheap type you buy from Wal-Mart. I had a couple of those that were given to me by someone who wasn't going to use them. The plastic is very cheap, flimsy, and breaks easily. Not recommended unless you need catcher trays for drainage.
Which brings me to the last point: catch pans. You'll need bottoms for these containers to drain into so the water doesn't just sieve right through or end up on your floor. The coffee cans have lids that work perfect for this. We used the trays you can see in the background from the seed starters as well as old cookie tins. Unused lids from Tupperware, Rubbermaid tubs, and a lot of other things can be recruited for this as well. I even used an old oil pan (thoroughly cleaned) once.
This is a great, low cost, and easy way to get your garden going from seed. Plus, it's a great Saturday project on the porch for the whole family to get involved in.