Are there free (or low cost) sources for nursery pots? Presumably nurseries reuse them. I'd like to get a few dozen in varying sizes for starting vegetables.
Be creative -- my two favorite free pots for transplanting up (i.e. repotting tomato/pepper/broccoli/etc seedlings into a larger container) are milk cartons and yogurt tubs.
Half gallon cardboard milk cartons are the perfect size for tomatoes. I rinse them well, cut off the top, leaving 4-5" on the bottom. Drill a few holes in the bottom for drainage and you're ready to go. The only problem I have is that they don't "nest" -- storing a bunch of these takes up a fair amount of space. These are very durable; you must take the plant out of the box when transplanting, and the box can be reused for at least a couple of years.
2 lb yogurt tubs are about the same size. These just need drainage holes drilled in the bottom. These are easier to store: they nest, so you store a lot in a small space. These are durable as well; the only problem I've had is with cracking. When they crack or break, you can recycle them (assuming your local place takes #5).
Toilet paper rolls are an interesting idea; I haven't tried this.
I've seen several slightly different sets of instructions on making newspaper pots. As another answer notes, make sure your ink is soy based -- some inks are toxic.
Not as Good
The smaller single serving milk or yogurt containers are ok, but a bit small for transplants. Don't try to use metal cans (e.g. soup cans) -- these are ok containers for growing, but it's impossible to get a plant out when it's time to transplant. Egg cartons seem like a good idea, but they are just too shallow.
As other answers noted, ask at the nursery, ask your friends. Ask at the local deli, they may have tubs that they discard when empty. Keep your eyes open for containers that would be good for growing.
The downside to this approach (see below) is that you end up with a varied collection of containers and your plants are harder to manage.
Up Front Investment
You can have a never-ending supply of pots by simply not needing pots.
If you don't mind a one-time expense, check out soil block makers. These are a little hand-powered device that you use to compress potting soil into a cube. The cubes hold their shape surprisingly well and are a nice way to start plants. You can get small, medium, and large block makers, along with an indent attachment so that the small blocks fit into the next size up. This way you can "pot up" your tiny seedlings as they grow.
I've used the 2" block maker (makes 4 at a time) with good results. A friend borrowed my block maker this spring for use in his new greenhouse and started several hundred vegetable and flower plants successfully on his first attempt using this strategy.
I've also used the 3/4" block maker (makes 20 at a time) with good results. You can fit about 300 blocks on a cookie sheet -- that's a lot of spinach! Then, by changing out the insert on the 2" block maker, you can make 2" blocks that you can drop the 3/4" blocks directly into for another couple of weeks of growth before transplanting out to the garden.
Another way to go is to sidestep the individual pot and use trays (flats). Again this requires a bit of an up-front investment in time and/or money. You may have or be able to find scrap wood that is the right dimension to use for this project; just be careful to avoid wood that has been treated/preserved (pallets are sometimes chemically treated so they last longer).
In "How to Grow More Vegetables", John Jeavons describes how to use flats that you can build yourself. Make shallow trays for starting seeds and deeper trays for pricking out when the plants are ready to be potted up. I should confess that I haven't built the trays as described, but they don't seem to require much building skill. I instead used some containers (old window boxes) that I had around the house that matched the depth specifications from the flats in the book. I followed the recommended spacing from the book for plants in flats, and everything transplanted into the garden easily. Also take note of his cautions and consider building the smaller size flats: an 11x22x6" box full of moist soil will be deceptively heavy!
The big advantage of trays over something like milk cartons or a collection of individual containers that you've scavenged is uniformity. They're:
- easier to move in/out of the house when hardening off
- easier/faster to water
- faster to set up -- fill and plant
- more flexible -- tomatoes need more room than basil, you don't need to "waste" a 4" milk carton and all that space/soil on a single basil plant
- easier to plan around -- you can set up your shelves and lighting based on the size of the trays (e.g. four trays to a shelf/light) or if you're building trays and already have shelves, you can adjust the size of the trays to what you have for shelves so that you can fit an even number into a shelf with no wasted space
The only disadvantage that I've found is that if you're starting multiple varieties (e.g. I don't want 50 of the same kind of tomato, I want 30 paste, 6 of two different kinds of cherry, and 14 beefsteaks) it's challenging to keep the varieties separate within a single tray -- you should definitely have a separate planting container!
I've always had the opposite problem. After a few years of trips to the nursery, combined with the fact that the pots are not recyclable (at least they haven't been in the past -- not sure if this has or will change soon), I've had more of those things than I can ever reuse. There are enough gardeners in my neighborhood that we started an informal exchange. I would give my extras to a neighbor who gave them to a friend who needed a few.
So, I would start by keeping what you get from the nursery and talking to your neighbors to see if they have extras that would otherwise wind up in the trash.
I'd also recommend you look into (non-petroleum) alternatives. I've tended to use peat pots more often than the plastics, and they have the advantage that you can just plant the whole thing in the ground where it degrades.
Another thing I have read about quite often, but haven't tried is using newspaper. Again, it is something that will biodegrade around the plant. Here are a few links on how to do this:
I have to admit that I've always kept a number of gallon pots for plants that I have to keep indoors until later in the spring (such as tomatoes), plants that would be too big for either peat pots or newspaper pots.
Check with your local nursery too. I've heard of some nurseries that take back pots for reuse and to keep people from just throwing them away.
Like rsgoheen I have too many. So I would suggest that the average gardener is in the same boat as us two. If you have any gardening friends or friends of friends then just ask them. It's likely they'll be all too pleased to get rid of some of their build up.
or ask a Nursery
I wanted a few free polystyrene trays at the start of spring, so I asked my local nursery if I could have some of their old ones. It helped that I was buying some stuff there too. They let me have half a dozen.