The solution to this problem is very simple, but it does require diligence on your part...you need to either keep a garden journal, use plant markers for every plant in your garden, or (even better) BOTH. And, you don't have to spend a ton of money to do it, either. Here's the low down.
Garden Journals...this is a rather a vague term for keeping some sort of print or electronic record of what you plant. You can keep a bunch of loose papers in a box, use a binder, buy a diary, or use a computer program designed for keeping track of your plants...choose according to your budget. Where you keep the details isn't what's important...it's what details you keep that are. Here's a basic list:
- The date you planted a seed, seedling, or plant.
- Where you obtained the seed or plant (keep receipts if plants have guarantees).
- Plant type: Annual, Perennial or Biannual.
- Sun, soil and water requirements (in case you need to transplant).
- Plant characteristics: Latin and common names, foliage colors, bloom time, bloom colors.
- Harvest dates (if applicable).
- General observations during growth period.
Plant Markers have been used for centuries, and are perfect when used in combination with a journal. Why do you need both? Because garden markers are movable (someone is bound to monkey with them at some point, be it a two year old or a cat or a bear) and any custom writing on them will wear off eventually. If you stay on top of things, you'll be fine...those of us who live in the colder climes (yeech) have to deal with the effects of snow and cold on the writing of our markers, and it's a good idea to get out there as soon as the stuff melts to check on them. Those of you in the south have to deal with the sun and its effect on them, so check often for fading.
The varieties of plant markers are incredible...I've chosen to list my personal favorites for you, and I've had great success with them here in Pennsylvania.
- Wooden Stick-style Markers...they come in all sizes from tiny to huge, and I love them for pots and seeds. Best to use a Sharpie type marker on them, and they'll only last a season at most. Good for two markings only, one on one side, one on the reverse. Very inexpensive, so it doesn't feel like a waste of money when you have to toss them.
- Steel and Zinc Cap Style Markers...also in a variety of sizes ( I like the 10 inch high best), these have steel wires that go into the ground and a zinc faceplate you can write on. The plates aren't the biggest, but they do just fine. Can be used with a Sharpie or Paint Pen, but there are carbon pencils available that you can erase so these are reusable. Markings last only one season around here, but you can write over the top of the old ones to 'refresh'.
- Steel and Copper Markers...these 10 inch high markers have steel wires and larger copper faceplates that you can either write on or emboss with a ballpoint pen. Very cool, and develop a lovely verdigris over time. The embossing lasts forever, so make sure you spell things properly. Adds a touch of elegance.
- Stainless Steel Botanical Markers...smaller than most, these are about 6 inches high, but they are the BEST if longevity is what you seek. They won't rust or tarnish and will look just as good as the year before when spring arrives. Best used with a paint pen, which is removable with mineral spirits, so you can reuse at your whim. Very pretty, with lots of room to write.
- Plastic Markers...I normally don't like these, but there's a new one to market called PlantID that comes in a set with durable paper-like faceplate inserts you can write on, or use the pre-printed ones that are provided for you. A great idea, weatherproof, 8 inches high or so, and they're green plastic so they don't look cheesy. The little white ones nurseries use are handy for seedlings, but they don't function well in the garden at all and I lose track of them constantly.
Hope this helps...and happy gardening!