I only do plant tags inside containers and write nothing on the outsides. I cut strips from large yogurt containers and write on them with a "garden marker". It writes like a sharpie but does not fade in the sun like sharpies. Paint pens smudge too easily when wet for me. It would write well on plastic knives too.

Reason I like the yogurt cup strips is that the plastic is kind of bendy for at least a couple of years and won't break easily if I step on it. I shove them in pretty deep so my beds don't look too much like a mouse graveyard. Then I can pull them out a bit if I need to see them.

Tried making those nicer tags one year with foil duct tape and wire to write with impressions. Was smoothing the tape down and got one of the nastiest "paper cuts" ever. Bled like a stuck hog. Never did that again!

I use popsicle sticks tucked along the edge because sometimes I have two or three seed varieties in one jug so that makes it easy. After years of problems, I now keep mine just under a carport, right under the edge of the roof and don't have the problems with outside labels washing off. The seedlings do well with bright light but no direct sun or rain etc. Its very easy to cook seedlings around here with winter warm periods and this keeps them more consistent with no water-sogged soil. More often our winters have extended dry periods and this prevents soil from drying out. Later in the year I will move them out to an area of dappled sun.

I label low on the outside of the jug with a paint pen. That way when the tops come off I still know who is who.
You could label inside the jug with an old mini blind cut in to strips and a pencil. That won't fade in the sun either.

I use a paint pen on mini blinds, too. One set of mini blinds, new, is around $4 and will make enough tags for a few seasons.

Caryl

I also use plastic mini-blinds and #2 pencil. They last about 2 years. But like molanic stated, it does look like a mouse graveyard. I came across this tuturial using plastic knives and aluminum duct tape that might look better and last longer.

Here is a link that might be useful: Aluminum Duct Tape Plant Markers

I used a black marker and wrote on a small peice of paper and took clear packing tape and secured it to the lower part of my containers. They were snowed on last night and the lables look great! So far so good!

last year my garden looked like a mini grave yard too. This year I waited until "picnic' season was over, and picked up some knives and spoons that are different shades of green on sale , I got 50 of each for less than 2.00 a pack. I will give them a try this year. Hopefully they will blend in well enough, but be easy to read.

I wrote on the outside of each jug twice in paint pen. One label up high so I can quickly identify what's what, and one label down low for when the top comes off. This is my first time with this method. In the garden, I've begun using plastic plant labels written in paint pen for uniformity.

Martha

Like Molanic, I fashion my own labels from discarded liquid detergent/fabric softener/cooking oil containers. I have a template of a store-bought label, and while watchig TV I cut them out. I use a garden pen from Lee Valley which remains through sun, snow, and rain. I have not had to make any new onces in the last couple of years because I re-use them. They go from container to the garden and are washed at the end of the season for re-use. They last for many years and need replacing only when the plastic gets brittle and breaks. I use 2-litre pop bottles as containers so I can see the tag without opening it. Works for me.