CARE OF HOUSE AND GREENHOUSE PLANTS
Light and Sunlight
Plants need daylight to make energy; they can’t grow without it, or its equivalent in artificial light. They need some sunlight to set buds, and can’t flower without it or a substitute. Intensity and duration of light should vary according to each plant’s preferences.
No plant of ours is left to waste its life away on the fireplace mantel, where the light is too dim to read the printing on a book of matches. Granted, we might set it there for a day or so as a decoration, but we would return it to its bright window sill before it began to stretch out weakly in search of light. These are the signs of insufficient light—weak, lopsided growth; leaves that feel limp and look pale; new leaves, if any, growing progressively smaller and smaller; long leaf stems and long internodes.
Our window greenhouse, which faces south, is reserved for flowering plants that need all the light and sun we can give them, particularly in winter. This is Connecticut, remember; the winter sun seldom gets very hot or stays bright very long. And there are days on end when the sun simply does not show its face. California’s “shade plants”—begonias and fuchsias, for example—require full sun during a Northern winter.
For plants that are not quite so greedy for sunshine, we have the east-facing playroom picture window, which is lightly shaded by a high-branched deciduous tree in summer. For foliage plants, and a few others that will thrive on little or no sun, there are several other windows around the house where there is plentiful daylight, but the sun is seldom seen.
Your situation may be entirely different—perhaps a glassed-in porch that’s brighter than our window sills ever will be; or a contemporary-style glassed-in entry that lets sun stream in all winter long. Keep in mind that various plants have varying needs for light and sunlight; and the only sun that benefits a plant is that which falls directly on it. A south window may actually be shady in summer, and this is truer the farther south you go.
Temperature
Some plants grow their healthiest when the thermometer reads 50 to 55 degrees at night and 5 to 10 degrees higher during the day; some tender tropical émigrés suffer a chill when the mercury dips under 60 degrees at night. But the greatest number will tolerate a fairly wide range, and are quite content with whatever the house has to offer. This again assumes that other conditions, such as humidity, are kept up to the plants’ requirements.
Temperature tolerances are directly affected by the humidity in the air. Many plants will accept a temperature that is higher than average if the air is moist. Some will accept a temperature that is below average if the air is not too moist. In air that’s too hot and dry, leaf edges will often turn brown and crisp; when it is too cool, a plant may stop growing temporarily; when it is both too cool and too moist, there may be danger of rot. Don’t trust the thermostat that governs your house heating system to tell you whether the temperature is right for a plant; measure it on the very spot where the plant is growing.
Humidity
This is often a more crucial factor than temperature, and one that is more troublesome to change. Relative humidity is a measure of the amount of moisture in the air as compared with the maximum amount of moisture the air can hold at a given temperature. It is expressed in percentage figures.
Most plants find it difficult to breathe in dry air; they need some moisture around, on, and in their leaves. (People are better off when they have it, too.) Alone, or teamed up with unsuitable temperature, low humidity can cause leaves to wither, buds to drop before they open, and even an invasion of mites or some other pest.
A humidity gauge is not nearly so familiar a household item as a thermometer, but it is equally useful, usually better looking, and not much more costly. And it can come up with some eye-opening information. The humidity gauge will tell you very quickly, for example, when an air-conditioning system is missing its recommended mark of 50 per cent relative humidity. It will stop you from overwatering in muggy weather. It will show you that humidity can be dangerously low in the window where your plants are growing, even though it is perfectly acceptable three feet away. (Perhaps there is a radiator beneath the window.)
What you do to increase humidity depends on how low it is, and on what type of plant you are growing. At our house we have three systems for the humidity problem—the lazy, the halfway, and the necessary nuisance. The lazy way works fine for dry-air-type plants such as most cacti and other succulents. We simply grow them where the hot blasts from the radiator are strongest. They don’t wither, and when on sunny days we water them, we also mist them with a fine water spray. (For an easy misting device, we have an old Windex bottle with a spraying attachment in the cap. It does a fine job. Of course, there are other commercial products with built-in sprayers. Perhaps you have one in your kitchen.)
To go “halfway,” you set up some simple humidifying device. The containers which you fill with water and hang behind the radiators are effective to some extent. But don’t forget to keep them filled. Pans of water on top of the radiator also help. A steam kettle, such as you use when the kiddies have a chest cold, can be used for a few hours. But remember, that steam is hot, so be careful not to get it too close to your plants. Just keep it in the general vicinity; please, not too close! Here is something else we often use—put some gravel, sand, perlite, or vermiculite in a plate or platter, pour in some water, and put your flower pot in it. The water will evaporate and moisten the air around your plant. If you have a number of plants, get a metal or plastic tray. If you have a decorative garden, you might want to have a tray made to order, to fit your space. Paint it a pleasing color. I have seen such trays decorated with decals, but personally, I’d rather rely on my plants for the necessary decoration. In having a tray made—we’ve had several made by our tinsmith—the larger the tray, the better.
The “nuisance” system is usually necessary only for very delicate tropical plants that flourish in highly humid jungles and rain forests. They will need the platter, or tray of moist sand, plus some enclosure to hold in the moist air. For a single small plant, this can be an inverted bell jar, or a tent made from a polyethylene bag (the sort vegetables are often packed in) and propped over the jar and plant. A larger bag can be used to protect several plants. You can even use kitchen-type plastics such as Saran Wrap. A collection of tropicals almost calls for an indoor greenhouse, like the oldtime Wardian case. In our window greenhouse we can close the inside sash and, with the aid of pans of water, keep the humidity just about where we want it. On cold nights the electric-coil heater isn’t always adequate, so we open the sash to get the benefit of the heat of the room.
The plants that need this extra humidification are definitely in the minority; most are content with simple measures, or none at all.
Soil
When I first became interested in a wide variety of indoor plants, I prepared soil mixtures with the care and precision I had used in making the formulas for our children. It involved trips to the woods for leaf mold, sifting and mixing ingredients, and sterilizing the ordinary soil which we used in order to kill the seeds that are found in almost all soils. In our Long Island home we had an extra stove in the basement which we used for canning and other secondary purposes. I’d fill the oven with old baking pans and other receptacles which contained my potting soil, and light the burner. Frankly, it “reeked” and the reek was all over the house. It was as though we were burning feathers in the fireplace. Now that I am less energetic, and somewhat wiser, I buy prepared soil.
I find that for a reasonable number of plants the prepared soil is not costly and saves a lot of time and preparation. Of course, if you are a professional you may have your own ideas about soil, and your own formulas for a mixture. I’ll admit I do a little mixing on my own, but that is because I grow many different kinds of plants in pots, and each has individual preferences. Most cacti and succulents need something sandy that doesn’t hold moisture too long, as is natural in their desert homes. Tropical plants need a light, porous medium that is rich in moisture-holding humus, like decayed leaves on the jungle floor. Some plants get nourishment only from acid soil, some need alkaline soil, some like soil nearly neutral. I’ve found Michigan peat moss a good starting base regardless of requirements of individual plants.
I like to dish it right out of the bag. When done, I always pull the plastic inner liner together to keep it moist. In extra dry weather I often wet a sponge and put it on top of the mixture. Potting is a pleasure, because Michigan peat feels so soft, silky, and clean. At repotting time I discover well-developed, healthy root systems.
For plants that require better-than-average drainage—mostly succulents—I mix peat moss with builders’ sand. (Want to know where I got my last batch of builders’ sand?—from a contractor who was building a house down the road. He and his wife happen to be begonia lovers and he was charmed to know about my book All About Begonias.) The formula for the mixture is two-thirds soil and one-third sand. For even greater aeration, I may throw in a moderate ration of crushed charcoal.
On the other hand, some of my plants insist that their soil always be moist. For them I add coarse vermiculite, perlite, or Pelonex, and in a similar ratio. These soil conditioners have the ability to hold moisture without making the soil muddy or soggy.
There is another item on my potting-soil shelf—a jar of horticultural lime. This is for plants that dislike acidity. I either add it to the potting soil—a scant teaspoon per three-inch pot—or mix it with water, to be applied later. With or without these added ingredients, I feel that a good potting soil has sufficient nutrients for almost any plant for several months; so I seldom mix in fertilizer of any kind.
Potting
When and how to repot a plant should be the least of a gardener’s problems. Here is a case where hovering, pampering, and fussing usually does more harm than good. Plants are often better repotted mañana than today.
I know many of my plants have benefited from the fact that I have been too busy to repot them whenever the impulse came over me. I hate to think how many I have killed with kindness in my less active years.
Remember my Aunt Minnie? She embarked on a big repotting spree every spring, but not very often in between. Some of her most handsome specimens have lived in coffee tins and large juice cans for years. Instinctively she knows when a plant should be repotted. Don’t ask me how she knows it. And when that time comes, she goes about it in a firm, no-nonsense manner, firmly but tenderly.
There is one sure way to tell whether a plant needs a new pot. Turn the old pot upside down, tap the contents loose, and examine the soil ball. If it is completely covered with a network of roots, get busy with a larger pot. If not, don’t repot, just slip it back where it was before and give it a loving pat. If you happen to have a seedling you have great hopes of raising to a beautiful maturity, it will have to be repotted more often.
The kind of pot is a matter of personal choice. Plastics are lighter in weight, easier to clean, and capable of keeping soil moist for a longer period of time. This makes them suitable for moisture-loving plants, or for gardeners who have a tendency to forget the watering pot. Clay pots are porous, and because they let air seep into plants, they dry out faster. This makes them best for dry-growing plants, and for overwaterers (like me).
Actually, the size of the pot is more important than the type. It takes an expert to know how to water a plant when it is overpotted. You are not doing your plant a favor by housing it in a pot several sizes too large; in fact, you may even be signing its death certificate. As a rule, the new pot should be only one size larger than the previous one, thus leaving just enough room around the roots for some fresh soil. Pack the new soil firmly with your finger tips, a pencil, or a slim piece of wood. Be sure there are no empty air-pockets. Water it thoroughly and set it in a light, but not sunny, spot, for about a week. This will give it time to recover from any transplanting “shock.”
This discussion about overpotting applies to plants in general, but it is even more important with miniatures. Smaller pots will keep them down to natural, miniature size.
Fertilizing
Many people who have fewer plants than I—and more time—tend to make a fetish of fertilizing. I am afraid my methods are haphazard, and not to be recommended. Anyway, I will tell you what I do. Follow it if you like, but quite possibly you may have a better method which you prefer.
I keep two kinds of house-plant fertilizer on hand—a reliable brand of soluble commercial chemical plant food (it dissolves in water and has the note “trace elements added” on the label) and an organic food. This organic food is either manure water or fish emulsion. The fish emulsion comes bottled and is diluted with water. As an amusing sidelight, our tomcat goes slightly out of his mind when around a potted plant that has had fish emulsion for its dinner. The cat just can’t find the source of that aroma. Manure water, on the other hand, has no such fascination. It is easy to prepare. Simply wrap a portion of well-rotted manure in a section of cheesecloth or burlap, and steep it in the watering pot long enough to produce a “tea” fluid. Better do this out of doors, in the garage, or in the tool shed. It is usually “olfactorily offensive.”
Once a month I make a solution of the chemical fertilizer, at half the strength recommended on the label of the package, and feed plants as I water them. Two weeks later, and once a week after that if they need it, I feed with the organic solution. This, I think, constitutes a “balanced diet” for most types of plants.
Like overpotting, overfertilizing can lead to lost plants. It is my observation that an underfed plant usually doesn’t die quickly. It simply slows down until you have time to feed it. It is particularly important not to fertilize plants that have been repotted recently, plants that are unhealthy or are plagued by insects or disease, plants that are resting right after flowering, plants that are dormant or semidormant, as some of them are at certain times of the year. Do fertilize plants that are in active growth, setting buds, or in full bloom, plants that are aglow with good health, plants whose roots have filled, or nearly filled, their pots.
Watering
My children, who are learning to care for plants rather early, have been grounded in one fundamental fact—feel the soil in the pot to see if the plant needs water. If the soil is dry, fetch the watering pot (succulents can be an exception). I have been told my kiddies have had arguments at school about watering the plants which cluster on the sunny window sills. The usual procedure in our Redding school is to assign the care of the plants to a different child each day. He, or she, floods everything with water and then retires to his, or her, desk with the feeling of having done his, or her, good deed for the day. Plants, alas, are not like goldfish. They don’t care for swimming.
This brings up a question I am frequently asked about house plants: “How often should they be watered?” Even an IBM calculator with a thousand cards feeding through its maw couldn’t come up with a better answer than this simple statement: “Water them when they need it.”
At the risk of repeating myself, I will sum up my thoughts on this problem, and then go on to other subjects. Test the soil with your fingers, if it is dry, you can most likely water with impunity. If moist, more water is inviting root rot. When you water, make sure the entire soil ball is so saturated that excess water runs out the drainage hole in the bottom of the pot. Miniature plants are likely to require more frequent watering, because their pots are small and they are small. Frequency of watering: Here we get into an awful lot of tangibles, and some intangibles. There are such things to consider as the type of plant and its moisture needs, size of the plant and its pot, what sort of soil is in the pot, is the plant root-bound or not, is it in active growth or dormant, what is the weather like out of doors—is it warm or blustery, clear and sunny, dark and humid, or just another day. Remember, on hot dry days the moisture is going to slip away into the atmosphere. On cloudy days it will hang around longer; humidity will take care of that. If you feel your plant needs water and you are afraid of flooding it, you might try another device. Put some moist peat in a larger pot—or you can use vermiculite or perlite—and set the plant and its pot inside this larger pot.
Right now you may be wondering about hanging baskets and those plants that are wrapped in osmunda and mounted on slabs of wood. Give them a good dunking in the kitchen sink but let the excess water drain off before you hang them again, out of deference to your carpeting and furniture. Actually, the plants don’t care whether they spot your furnishings or not.
If all of this is confusing, may I sum it up in a phrase: “Just use your common sense” (horse sense may be a better term). I know I have written a few books about plants and gardening, and countless magazine articles, but here is a very candid confession. Until a very few years ago I knew practically nothing about the subject. What I know I learned by reading books and magazine articles, and “doing.” I know I killed a few plants out of ignorance, but I killed more with kindness. Every time a plant withered and died I felt badly. But I considered it a lesson in what to do, or not to do. I tried to find the cause for the demise. Today I have the satisfaction of having raised thousands of plants to beautiful bloomhood, and largely because of the sacrifice of some obscure begonia, or petunia, a few years back. I have been acclaimed as having a “green thumb.” Actually I do not have a green thumb. No one has. I thoroughly dislike the term. I dislike the implication that a person has a God-given quality which makes plants grow. Making plants grow and prosper is largely the mastering of a few rules, and the use of a lot of common sense. I’ll grant you, much of your common sense comes the “hard way.” But it is fun. I bow most respectfully to those plants which I killed with ignorance and kindness.
Grooming
This is the “beauty-parlor” treatment for your plants. Fading flowers and dying leaves are as unattractive on a plant as those unruly ringlets in a woman’s coiffure. In fact, they are even worse. They take strength from a plant and are unsanitary. Remove them as regularly as you can. You’ll be adding to the welfare of your plant. If the plant is of a type that needs to be pruned or pinched to keep it comely and compact, perform the operation before the branches get that gangly, middle-aged spread. Pinching out the new growing tips, either with sharp fingernails or sharper scissors, usually produces two new branches. If you pinch out the tips of these, you will most likely get four new branches and your plant will become pleasingly plump. The exception is the plant that blooms from the ends of new growth. Stop your pinching before the bud-setting season.
Not many miniatures need staking to keep them upright. If stake you must, do it as inconspicuously as possible and tie the stems neatly in their natural growing manner. Train miniature creepers in the direction you want them to grow, and miniature climbers up their supports. Rinse foliage with a fine spray (use that discarded Windex bottle I described earlier) as often as you can to wash away dust and dirt. Please, may I throw in a plea right here—recently I saw a commercial product which some people use to make their plants more green. It is a spray for foliage. For the moment it makes plants look green with its sheen. But it also clogs the pores on the plant and its leaves. For the moment it is beautiful; for permanency it is harmful. Decide, do you want your plant to live for the moment only?
Insects and Disease
Not long ago, when visiting a friend, I was taken out to her sun room to see her plants. She was proud, but I was shocked. What I saw was the most amazingly bug-ridden collection of fuchsias and geraniums I have seen in many a moon, plus a few poor distorted other flowers which were trying to survive. My poor hostess, honestly, I think she had no idea of her problems and the future of her plants. In fact, they had little future. I thought over that problem for a spell, and then told her the facts of life. Fortunately, she was able to save much of her greenery.
That poor gardener was on one end of the spectrum. On the other end are the overanxious ones who treat their plants with so many sprays and dusts that the leaves never get a chance to breathe pure air. Fortunately, in between there are the sane, sensible growers who are able to cope with the insects and diseases which beset house plants. As for myself, I have been at both extremes.
I now find prevention is the best protection. That is an old saw, but the best one I know. I keep plants and pots clean, remove dead flowers and foliage before they decay, and use germ-free potting soil. People often give me plants. I accept them most politely, and gratefully; but I am cautious about mingling them with my other residents of the greenhouse and window garden. I keep them in a quarantine section for a few weeks. No use asking for trouble, and I trust my friends understand.
For immediate and reliable treatment, I rely on an “all-purpose” house-plant spray or a dip. As long as I am careful to keep it up, I seem to have no great problems. When I get careless, as humans are wont to do, I regret it.
It is very convenient to rely on the new aerosol bombs—those that are specifically marked for house plants, and not those for household insects. There are several reliable brands, each listing on the label what they are to be used for. If there happens to be an added fungicide, so much to the good. That will cover just about everything.
A few words of caution about the use of aerosol bombs. Follow the instructions on the label to the letter. Hold the bomb at least eighteen inches away from your plant, maybe more. Some of those fluids come out of the can at a very low temperature and have the same effect as a blowtorch on foliage. Try to make sure the spray hits all parts of the plant. Remember, leaves also have an underside. Don’t let bugs use that underside as a hide-out.
There was a word of caution on each aerosol container I have seen: “Do not throw into an open flame when empty.” My husband wondered what would happen if he did. He tossed an empty can into the trash burner and got behind a tree. The explosion sounded like a hand grenade left over from World War II and he had to get a new lid for the burner. Please take my word for it and don’t take that chance. Let him be crazy if he likes, but not you. I don’t like to lose readers so early in my book.
I know I take precautions, but in spite of everything my plants become infected at times. When that happens it’s helpful if you can recognize the symptoms, diagnose the ailment, and apply the cure. With your interests in mind, I have put together a list of sorts which includes the most prevalent house-plant insects and diseases, the telltale signs of their arrival, and the insecticides and fungicides which will send them to their happier hunting grounds. If I have skipped anything, my apologies. If you are having special problems, phone your local county agricultural agent. He is a good man to know anyhow. But please, unless you have something that is out of hand, don’t bedevil the man. He is probably concerned with ticks on sheep, ringworm, hog cholera, breachy cows, grubworms, and forty people who want to know why their hollyhocks didn’t bloom.