Having raised and given numerous plants to friends over the years, it pleases me when I see my plant thriving in its new home. But it often happens that my once-vigorous plant is found struggling to survive. What happened? Typically, one of these general blunders occurred:
Beginners often routinely repot after getting a new plant. This is not always necessary, especially in the dead of winter when it's cold and the plant is not growing rapidly. Repotting in cold conditions could invite rot, especially in too-wet soil in a too-big pot. Check to see if the plant really needs to be repotted: Does it look healthy? Are the leaves sturdy and firmly attached? Is the soil moist and loose? If the answer is yes, then it won't hurt to wait until winter has passed and warm temperatures inspire potted plants to flourish.
If repotting is necessary, be careful not to repot the plant in a pot several sizes too big. This is generally a sign that the budding plant enthusiast has great faith. It stands to reason that if you put your tiny plant in a giant pot, it will grow to fill the space, right? But that invites disaster. When you water such a plant, you'll end up with a lot of mud. Wet plus cold equals rot, especially in winter. Get a pot that's just one size bigger; don't skip sizes. Go for a pot that is ½ to 1 inch larger in diameter, measuring across the top of the pot.
When choosing soil, there are a few things to keep in mind. First, do not use dirt from outdoors. Even if it looks okay to use, outdoor yard soil is full of insects, weed seeds, and microbes. This would invite too many unknowns into your plant's container and into your house.
Secondly, invest in good potting soil; it's only a few dollars extra. I, too, was once a beginner who used the cheapest potting soil I could find, but nowadays I purchase orchid soil for my indoor plants. You don't have to have orchids to use orchid soil. It's a wonderful, chunky soil with pieces of bark added in for good drainage and works well for most indoor plants, so leave those nice chunks alone—don't pick them out. For indoor cacti and succulents, cactus soil is a good choice. It looks like regular potting soil with sand added in for drainage.
Here's why drainage is so important: A plant's roots need air as well as water. Yes, you want to give your plant water, but you also want that water to drain away freely so that the roots can breathe again. Although a beautiful pot might be what inspired you to repot in the first place, if that gorgeous pot does not have drainage holes in the bottom, it will spell disaster for your plant. A nice way to have both a healthy plant and an attractive pot is to plant your specimen into a plain, sturdy plastic pot with drainage holes and then lower that inside of the decorative pot, like an insert. You want to be able to lift the potted plant out again for watering. Place it back into the decorative pot after it has stopped dripping.
About drainage stones—aquarium stone or pea gravel is good if you want to place a layer of stone in the bottom of your pot to prevent the potting soil from washing out. However, if you use orchid soil, drainage stone is not necessary. Place a few large pieces of bark from the bag of orchid soil in the bottom of the pot before adding more orchid soil in. Some soil will wash out at first, but then everything settles in nicely after a few waterings. For in-depth information about container gardening, soil, and drainage, the Container Gardening Forum here on Dave's Garden is a wealth of information.
When to water? Beginners tend to water their plants daily, on an automatic schedule, like clockwork. However, many times, you must get touchy-feely with your plants. Go ahead—place your finger in the first half-inch or inch of soil to see whether it feels moist or dry. There you go. Now you are connecting with your plant's needs. Is there some moisture in the soil? Then you don't need to water. Is the soil bone-dry? Then you do need to water. You will soon learn to water when the time is right which has little to do with a schedule.
Finally, a novice will frequently place his or her newly-potted plant on an end table, countertop, or in a corner for decorative purposes rather than for meeting the plant's needs for sunlight. The plant might look good in that dark spot for a few days, but not for a few weeks. You must try to duplicate nature: Give it sunlight. Otherwise, it will become light-starved. This leads to a condition called phototropism, or in plain English, your plant will get spindly and weak as it stretches and bends to find enough light.
So, place your plant on or very near the windowsill if at all possible. Many times, that will be in sunlight coming through a south-facing window, the side of your house that gets the most sunlight during the day. In addition, consider that the plant is already challenged by living indoors and receiving light on one side only. Therefore, it is best to periodically turn your plant so it doesn't lean one way or the other.
Some plants don't need that much light, though. A southern window might stress them. Those types should be placed in filtered sunlight from a north, east, or west window. Dave's Garden is an excellent place in which to do a search on your particular plant to find out how much light it needs to stay healthy. If you don't know the name of your plant—not a problem! You can browse through the PlantFiles photos here to identify your plants, and you may access many of the forums when you register. With a subscription, you may upload a digital photo to the Plant and Tree Identification Forum for more help.
Just a few pointers from a former beginner with a history of many bloopers! But bloopers can be overcome through information and trying things out. My intention is to leave you with a nugget or two of wisdom as you begin to discover your own green thumb.
Special thanks to Jeremy Wayne Lucas and LariAnn Garner whose articles are referenced above with hyperlinks.
(All plants and photos are my own; botanical names appear as screen tips. The Astrophytum asterias cactus was planted from a seed packet labeled, "Mixed Cactus Seed" in 1991.)