Indoor plants add color, texture and warmth to the home. They allow year-round access to gardening and can even improve air quality. Many houseplants are easy to grow, but they must be given appropriate care in order to thrive. Since your plants were probably started in a greenhouse — grown under ideal conditions — moving them into your home takes a bit of adjustment on their part.
Proper watering and lighting are the most important components of indoor plant care, but humidity and temperatures also play a role. The trick is to try to mimic the climate of the place that plant came from.
Tropical plants thrive in warm, humid environments, while cacti and succulents prefer hot, dry climes. Of course, your home can’t be everything to every plant, but you can take plant needs into consideration when choosing plants. And, with a few tricks, you can convince your green friends that they are living in their ideal environment.
The first thing to consider when selecting a houseplant is where you want to put it. Then match the space and lighting with the plant’s requirements. Do you have a big spot by a sunny window or a small space with moderate light?
Next ask yourself if you are looking for a plant with beautiful green leaves or would prefer a flowering plant. Some flowering houseplants are seasonal while others will bloom year after year (see Top Choices for Easy Care Flowering Houseplants).
A third consideration is how much time you can devote to a particular plant. A spider plant will take almost any amount of care (or neglect), while an orchid requires significant tender, loving care.
Indoor Plant Care
Potting soil should be kept moist, but not wet. Of course, there are always exceptions — succulents, and other thick-leafed plants do best when the soil dries out between watering. If the soil is kept too dry or too damp the plant’s roots will begin to die, which can lead to inadequate growth or even death of the plant.
There are several methods to determine when a plant needs water. If the potting soil becomes lighter in color or cracked, it’s probably time to water. Pick up your plant and gauge the weight after watering. After a few practice lifts, you’ll be able to tell if the plant needs water just by picking it up. Of course, you can always stick a finger in the soil to determine how moist it is below the surface. For large plants, a hand-held moisture meter may be your best bet to determine how much water is present around the plant’s root mass.
Do NOT let plants get to the point where they are wilting or the soil is pulling away from the edge of the container. These symptoms indicate dehydration and at this point the plant is already seriously stressed and the roots may be damaged.
Signs of underwatering include:
- Slow leaf growth
- Translucent leaves
- Premature dropping of flowers or leaves
- Brown, yellow or curled leaf edges
Too much water is just as detrimental as too little. Frequent watering forces air from the soil and opens the door for root-killing bacteria and fungus to move in. Overwatering is the number one killer of houseplants.
- Signs of overwatering include:
- Fungus or mold on the soil surface
- Mushy brown (maybe stinky) roots at the bottom of the pot
- Standing water in the bottom of the container
- Young and old leaves falling off at the same time
- Leaves with brown rotten patches
For those who are too busy to keep up with a regular watering schedule, which requires checking individual plants every 3-4 days, there are several self-watering devices available. A moisture wick draws water from a dish of water into the root ball of your plant. Capillary mats and moisture tents also keep plants watered. You can always make your own self-watering plant container out of a 2-liter pop bottle.
Room temperature tap water should be fine for most indoor plants, even if there is chlorine or fluoride added to your city’s water. Plants especially love rainwater or melted snow (unless you live in a region with acid rain). Avoid continuous use of softened water, which may contain sodium.
How to Water
Plants can be watered from the top down or bottom up. When watering from the top, try not to wet the foliage, while ensuring the entire soil mass is moistened. Water should be coming out of the drainage holes in the bottom of the pot.
If you prefer to let your plants do the work, set the plant in a dish of water and the roots (and capillary action in the soil) will pull up whatever they need. This method, known as bottom-watering, is a more thorough, if time-consuming, way to water plants.
Tip: Be sure to dump any standing water from the saucer one hour after watering.
Good drainage is essential to healthy houseplants. Start with a good, organic potting soil (not regular soil) that has been mixed specifically for indoor gardening.
Choose a container with drainage holes, or put a layer of pebbles in the bottom of a container without holes. The point is to not let the plant stand in water. From time to time, check that the drainage holes have not been clogged. And always empty standing water (don’t run it back through the plant’s soil).
As with watering, every plant has different light requirements. Many plants prefer direct sunlight, but this may be hard to get inside a house. Placing a plant in a window might offer enough light, but some houseplants will need supplementing from a grow light (see Lighting Indoor Houseplants).
Flowering plants generally do best in moderately bright light and for this reason windows located on the south, east or west side of the house are best for potted flowering plants. (African violets prefer north-facing windows.)
Foliage plants can be divided into three categories: those requiring low light, moderate light and high light.
A dimly lit room should suffice for those few plants willing to survive in low light areas. Moderate light-needing plants will prefer a north-facing window, light diffused through a thin curtain or daylight without direct sun. Indoor plants that prefer high light will need to be in a south-facing window or under a grow light.
Some plants will benefit from being moved outside in the summer to get a little extra light. Read about Moving Plants Indoors & Outdoors here.
Many houseplants thrive in temperatures between 65-75° during the day and 55-60° at night. Of course, temperature preferences vary from plant to plant with tropical plants liking temperatures around 90° (or higher) and other plants growing better in cooler temperatures.
Most plants thrive in high humidity — around 80%. Unfortunately, most homes are much drier, especially in the winter when forced heat can even further drop the humidity.
Using a humidifier can help, but there are other ways to increase the moisture in the air near your plants. A small tray containing pebbles and water can boost local humidity as can grouping plants more closely together. Daily misting of the plant’s leaves can help as well. For some plants, such as gardenias and orchids, keeping them in a bathroom or the kitchen (both usually have a higher humidity) can help.
Every time a plant is watered nutrients leach out of the soil. Even if that didn’t happen, plants would quickly deplete the nutrients in their soil. Unlike plants living outside, houseplants don’t have a regular source of nutrient replenishment unless you fertilize them regularly. (Newly purchased plants have been heavily fertilized in the greenhouse and can wait a few weeks before getting started on a fertilizing regime.)
Fertilize once a month when plants are flowering or growing. During the winter, when plants are dormant or generally not growing much, fertilizer can be withheld.
If a plant is dropping its lower leaves, showing weak growth or an overall yellow-green color, it may need more fertilizer. It might also need more light or less water, so take the time to analyze all conditions before pouring on more plant food. Adding fertilizer when a plant does not need it can be worse than doing nothing at all.
Tip: If a plant is wilted, water well first then apply a fertilizer later — after it has recovered.
Choose an organic fertilizer specific to houseplants and read the instructions carefully. While natural fertilizers are less likely to burn or harm your plants than a synthetic fertilizer, it is important to apply the correct amount. In general, plants grown in low light will not require as much fertilizer as plants grown outside or in bright light.
To start, use about 1/4 the amount of fertilizer recommended on the label once a month. Then, if overall plant color becomes lighter, increase fertilizer applications to every 2 weeks. On the other hand, if the new growth is dark green, but the leaves are small and the space between the leaves seems longer than on the older growth, fertilize less often.
Tip: Soluble salts from synthetic fertilizers can build up over time and create a crusty layer of salt deposits on the soil surface. Remove this layer and leach the soil every 4-6 weeks with generous amounts of water to help avoid toxic salt build up. Excessive salts can damage roots and make the plant more susceptible to disease and insect attack.
If your plants are thriving and growing the way you want them to, eventually they will need a bigger pot — or some fresh potting mix. Repot plants in the spring when they are just starting to grow. Vigorous root growth will allow the plant to adjust to its new container quickly.
When it comes time to repot, choose an organic soilless medium made specifically for potting houseplants (maybe even specific to your species of houseplant). There are many to chose from, or you can make your own (see Potting Mixes for Certified Organic Production).Choose a pot that is bigger than the current container, but not huge. A pot that is too-big can encourage root rot and other problems because the soil will remain wet for days, or even weeks before it can be used by the plant.
Take care with the root system when repotting to avoid damage. Carefully firm the soil around the root ball without compacting the soil. Leave enough space at the top of the new container for water and water thoroughly. (Click on Repotting Houseplants for step-by-step instructions.)
SUMMER PLANT CARE
Though some sun-loving plants like succulents and cacti are well adapted to high temperatures, plants that are kept indoors are not acclimated to the extremes of a summer heat wave. This includes your succulents and cacti (unless, that is, they’ve been moved outdoors onto the porch or patio for summer). Leafy tropicals are particularly susceptible to damage from heat, and if too severely damaged, might not recover.
Not to worry! There’s plenty you can do in advance of and during the heat wave to make sure your indoor plants survive the heat. Here are 5 of the most important summer plant care tips to get you started.
Promote high humidity
Plants that like high humidity (many epiphytes and tropicals such as fittonia, calathea and most ferns) should be frequently misted through periods of heat. You can also fill a shallow dish with pebbles, fill with water, and set your pot on top to create a little humid microclimate for your plant that will provide humidity and help your plants survive summer.
Water well, and water deeply
As you’ve probably read on our blog before, proper watering is key to indoor plant care. Though over-watering is the most efficient way to kill your houseplant, heat and sun cause water to evaporate from soil at much faster rates. In preparation for a heat wave, be sure to give your plants a deep watering – if you water too quickly or not enough, often just the top of the soil gets wet and the rest escapes down the sides of your pot and out the bottom. Make sure the water is actually absorbed by watering slowly, and allowing the plant to soak up excess water in a bowl for 10-20 after watering.
While you’re in summer plant care mode, check your plants soil moisture level more frequently than normal, either by using a moisture meter, or with the trusty “finger test” – water when soil feels dry at 1-2″ down for most tropical plants. Another key indicator of fast-drying, compacted soil is when the soil pulls away from the sides of the pot. If there’s a gap between the soil and the side of the pot, it’s time to rehydrate!
If you happen to have A/C, keep in mind that the dry air can dry pots out just as quickly as the sun. Keep an eye out for thirsty plants and water well.
Shade sensitive plants from too much sun
Plants get sunburn, too. Plants that live in south and west-facing windows will get an especially bright dose of vitamin D during this weekend’s heat wave. But since you can’t put sunscreen on their leaves, it’s best to move them a bit further into your house to spare them from this direct hit of the sun. As mentioned at the top, this goes for succulents and cacti that haven’t been acclimated to direct sun, too.
Keep it cool
If you’ve ever felt faint in the heat, imagine what your plants must feel like! Do your best to keep your plants out of the hottest spots in your home while in summer plant care mode. This might mean moving them away from windows or even into other rooms during hot times.
Also, it may seem counterintuitive, but the best way to keep your house cool in the heat (assuming you don’t have A/C) is actually to close your windows during the day when the heat is on, and open them back up at night when it cools down. If you can manage to get the house just a few degrees cooler, you’ll feel a lot better, and so will your plants!
Don’t fertilize during a heat wave
Though fertilizer is your friend, especially during summer, a stressed plant should never be fertilized until it recovers. When your plant is in summer survival mode, it’s not looking for extra nutrients and isn’t prepared to make use of them. Introducing these into the soil will risk further stressing your plant. Wait until it cools down a bit for your next feeding!
Don’t re-pot during a heat wave
Likewise, you shouldn’t choose a 100+ degree day as the perfect moment to re-pot that root-bound ficus (or any other plant for that matter). Why? Leaves always get damaged during re-potting (and in fact, proper re-potting often involves trimming away a lot of the root mass). Re-potting will cause your plant to get a bit stressed (even though it’s important plant maintenance in the long run) and this added stress could cause it to fail during the heat.
Wait to prune
Why wait to prune off damaged leaves and stems until after the heat wave passes? You guessed it: stress. While a little pruning here and there often helps your plant spur new growth, immediately assuming that a leaf that’s wilted or discolored is a goner is not the best choice during a heat wave. When conditions get back to normal, the leaf might rebound. Plus, it might still be supporting the overall health of the plant. And, of course, pruning does cause a bit of stress to your plant. It’s best to wait until temperatures get a bit back in the normal range before snipping off leaves and stems that didn’t make it.
Learn to recognize stress
Last but certainly not least, being ready to catch problems early is key to stopping them before they take hold and ravage your indoor plants. Common signs of stress to keep in mind for summer plant care usually have to do with too much heat and too little water.
– Tropical plants, especially those with tender leaves, usually wilt with exposure to too much heat.
– Foliage that was once bright green may look pale when stressed.
– Sunburn manifests in a variety of ways, but often looks like a rough brown or yellow patch on leaves/stems.
– Flowers (and leaves) often drop off or yellow when a plant is stressed