In order to thrive, all houseplants need light, water, soil, a container and the proper temperature and humidity levels. Our complete guide has all the information you need in order to meet those needs.
All plants need light in order to survive, but the amount of light they need varies from plant to plant. The amount of light you receive in your home or office is the largest deciding factor in what kind of plant you should consider.
Light can be divided into 4 categories:
- Low Light – Low light locations tend to be rooms with Northern exposure or shady corners while the rest of the room is brighter. Low light areas receive no direct sunlight.
- Moderate Light – Locations with moderate light have either East, West or South facing windows and are at least 5 feet away from those windows.
- Bright, Indirect Light – Locations that receive bright, indirect light tend to have East, West or South facing windows and are brightly lit most of the day, but do not get direct sunlight. If a spot does get direct sunlight, moving the plant a couple feet away from the window or adding a sheer curtain to diffuse the light will reduce exposure to the direct sun.
- Bright, Direct Light – Locations that receive bright, direct light have East or West facing windows, are brightly lit most of the day and receive direct sunlight.. In summer, these spots tend to get hot so it may be necessary to move the plant away from the direct light if it starts to decline.
An easy method to test for light quality is to hold an object in front of a piece of white paper and look at its shadow. An object in direct light will have a crisp, dark shadow with firm outlines. Indirect light will produce a shadow with less distinct outlines, but still dark and easy to identify. Objects in moderate light will produce a less distinct shadow and be a lighter gray. The shadow cast by an object in low light will be barely discernible and have no clear outline.
Once you know your light conditions, you can better select a plant for that space. Plants are very firm on their light preferences. Low light plants will wilt and scorch in bright, direct light. Bright light plants will fail to produce flowers, lose vibrant coloring and get leggy in low light.
Artificial lights are an easy way to mimic sunlight and increase sunlight in low light areas. Regardless of what type of light you use, all artificial lights need to be left on for several hours for maximum benefit.
- Fluorescent lights – The most common type of lights in offices. For best results, light should be placed approximately 1 foot from plants.
- Incandescent lights – Traditional light bulbs. Give off a lot of heat, keep plants several feet away from plants to prevent scorching.
- LED lights – An energy efficient alternative to incandescent lights. These bulbs give off less heat and can be used closer to plants.
- Halogen lights – Lights that mimic sunlight very well but can get very hot. Keep plants a few feet away from the light to prevent scorching.
- Grow Lights – Lights designed specifically for indoor growing. The best light choice for indoor plants.
Overwatering is the leading cause of plant death (indoors and out) so it’s important to water correctly. As indicated below, there are multiple factors that determine how often you will need to water:
- Plant – The plant itself is the main factor in how often you need to water. A succulent can go long periods of time without water while a fern will want to be watered more frequently.
- Soil – Potting soils are not created equally – some varieties will dry out faster than others.
- Container Material & Size– Containers made from concrete and clay will leech water from the soil, causing it to dry out faster. Larger containers hold more soil and will dry out slower than their smaller counterparts.
- Light – The brighter the light, the faster the soil will dry, and the lower the light, the slower the soil will dry.
- Temperature – As with light, the higher the temperatures, the faster the soil will dry.
- Humidity – Higher humidity levels can help the soil stay moist longer.
How to Water
Plants absorb water only through their root systems, so there is no need to wet the leaves when watering your plants. In fact, repeated wetting of the leaves of certain plants can lead to the development of fungal disease. Instead, water the soil directly, and aim to saturate the soil. It is better for the plant’s root development to be watered deeply and less often than it is to be watered a little bit every day.
Some plants, like African Violets, can be fussy about how they are watered. These plants don’t like getting their getting leaves wet, so you’ll have to water either very carefully to prevent splashing or water from the bottom. Watering from the bottom is as easy as using a self-watering pot, or setting a pot with bottom drainage into a saucer of water and allowing the soil to absorb water from the bottom.
When to Water
When you bring a new plant into your home or office, the easiest and most trustworthy method of learning when to water is to test the soil with a finger. Check the care guide for your plant and find out how much of the soil should dry before watering (i.e., just the top 1-2 inches, halfway, etc.). Stick your finger down to that depth and feel the soil’s consistency. If the soil is cool and damp, then it’s still wet and you don’t need to water. If the soil is dry and gritty, it’s ready for some water.
Keep track of how often you water over the course of a few weeks and you’ll have a watering schedule before you know it!
When it comes to houseplants, there are a few soil options to choose from and it can be a little confusing at first. Here’s a quick breakdown of the different types of soils you can find.
- All-Purpose Soil – A soil suitable for most plants. These soils retain a reasonable level of moisture, are lightweight and well-draining. Some All-Purpose Soils have added fertilizers mixed in.
- Cactus Soil – A fast drying soil suitable for desert plants like Cacti, Succulents and Aloe.
- African Violet Soil – Another fast-drying soil, African Violet Soils doesn’t dry as quickly as Cactus Soils, but is still faster than All Purpose. Perfect for not only African Violets but other plants like Cyclamen that enjoy being more on the dry side.
- Seed Starting Soil – Seed Starting Soils are lightweight and are made of extremely fine particles, this allows delicate sprouts and seedlings to grow easily. It is not suitable for long-term growth as the soil lacks common nutrients found in other soils.
- Orchid Mix – Unlike other potting soils, Orchid Mixes are less soil and more bark. This is perfect for orchids and other epiphytes (plants that grow on the surface of other plants like trees). Orchid Mixes replicate the growing environment of these plants and retain less moisture than traditional soils, allowing airflow around the root systems.
- Bonsai Soil – Bonsai Soils are another planting medium that can be surprising. Primarily composed of clay, pumice, lava rock and gravel.
In a pinch, All Purpose, Cactus and African Violet soils can be used interchangeably, but adjustments will need to be made when watering to account for the different drying speeds.
Top Soil & Garden Soil
A common question we hear from first time houseplant growers is: Can I use Top Soil instead of Potting Soil? The answer is a resounding “No!” Top soil retains far too much moisture, which will lead to root rot and plant death quickly. Top soil is also extremely heavy, weighing up to 4 times as much as potting soil, which can easily crush delicate root systems. The answer is the same for using soil from your garden; too heavy and too wet, with the possible addition of insects being present in the soil.
Plants require certain nutrients in order to be healthy and grow. In nature, these nutrients are easily found in soil and replaced as they are used up. Unfortunately this is not the case for potted plants, especially houseplants, as they are cut off from the steady supply of decomposing plant matter, insects and microscopic bacteria that produce these nutrients. While potting soils will have a good base for these nutrients during the initial planting, over time plants will use those nutrients up. Regular fertilizing will help your plants meet their nutritional needs.
What’s in Fertilizer
Fertilizers are comprised of three macronutrients; Nitrogen, Phosphorous and Potassium and they are commonly abbreviated as NPK. Nitrogen is primarily used for leaf development and color, Phosphorous for root, flower and seed development and Potassium for improving stem strength and disease prevention.
Fertilizers have different levels of these nutrients and the amounts are displayed in this format N-P-K. Balanced fertilizers are fertilizers with equal levels of the all three nutrients (like 10-10-10) and are a good choice if you have multiple different plants.
Plant-specific fertilizers, like African Violet Fertilizer and Orchid Fertilizer, have set amounts of Nitrogen, Phosphorous and Potassium tailored the those specific plants.
When to Fertilize
How often you fertilize will depend on the time of year, the type of fertilizer used, and most importantly, how often the plant wants to be fertilized.
Typically, plants only need to be fertilized spring, summer and early fall. During winter, plant growth slows, even for indoor plants, and with that slowing, the need for fertilization decreases. Either fertilize less frequently in winter or pause fertilization entirely until spring.
Fertilizers have different time frames for fertilization, with some needing to be applied weekly and others lasting for months. In general, organic based fertilizers tend to be longer lasting and non-organic fertilizers require more frequent application, but that isn’t always the case. Always check the products label to see how often it needs to be used.
Finally, and most importantly, is how often your plant even wants to be fertilized. Some plants only want fertilization once or twice a year while others want consistent fertilization year round. Check the care guide for your specific plant to learn how often they want to be fed.
- Ceramic – A glazed clay container. Larger sizes can be very heavy.
- Terra Cotta/Clay – Unglazed containers. Due to their unglazed state, clay and terra cotta can leech water from the soil, leading to the need for more frequent watering. Larger sizes can also be heavy.
- Concrete/Cement – Can be either glaze or unglazed. Unglazed containers can also leech water from the soil. Larger sizes can be extremely heavy.
- Plastic – Thinner and more lightweight than ceramic, terra cotta or cement.
- Resin – A plastic-like material that can be molded into many different styles and shapes.
- Hanging – Can be made of any material and come in multiple sizes and shapes.
- Orchid Pots
- Self-Watering Pots
- African Violet Pots
- Bonsai Pots
- Found Objects – Any bowl-shaped object can be used as a container as long as there is room for the plant’s root system. Depending on the item used, steps might need to be taken to create drainage.
- Wood or Metal – less common than other container materials and prone to damage from watering
Selecting a Container
When selecting a container, the two main factors to keep in mind are size and drainage.
Size – Container size is determined by the inside diameter of the container’s opening and is measured in inches. Most sizes are even numbered starting at 2”. When you select a new container, your aim is to pick one that is ideally only one size larger than the current container. So, if you have a plant currently in a 6” container, you want to select an 8” container for repotting. Selecting a container that is too large can lead to overwatering and root rot.
Drainage – Containers can be divided into those with drainage and those without.
- Containers with drainage are the preferred type for houseplants. Container drainage is the best defense against overwatering, as excess water will drain which allows the soil to dry correctly.
- Containers without drainage have an increased likelihood of overwatering as excess water has nowhere to go. Creating drainage in these types of containers can be done in several methods.
- Drilling a hole into the bottom of the container is the easiest method, but there’s a chance that ceramic, terra cotta and clay containers may break.
- Adding a layer of material (such as stone or marbles) to the bottom of the container creates a reservoir for excess water to drain into. However, that water still can’t drain out of the container and consistent overwatering can fill up that reservoir quickly, rendering it useless.
The majority of houseplants are from tropical areas and have higher temperature requirements than outdoor plants. Luckily, those temperatures line-up pretty well with the temperatures we prefer. With a few exceptions, most houseplants prefer temperatures between 60° and 85° F.
Because of their tropical origins, the temperature threshold for most houseplants is around 50°F and prolonged exposure to temperatures below that threshold will lead to plant decline and death. Even brief exposure to low temperatures, including drafts, can cause plant stress and damage.
Houseplants that come from tropical climates prefer high levels of humidity. This is especially true during colder months when everyone is turning on their heaters, which dries the air. There are multiple options when it comes to raising humidity levels in your home.
Humidifiers – The easiest method of increasing humidity is placing a humidifier nearby.
Pebble Tray – A tray or saucer filled with pebbles and water under the plant is another easy way to increase humidity as the water evaporates from the tray. To prevent accidental overwatering, it’s important to make sure that the container can’t leech water up from the tray. Also, make sure the tray always has water in it.
Misting – Regular misting with a spray bottle is another way to increase humidity for some plants. However, plants such as African Violets and Cyclamen do not do well with misting as they do not enjoy getting their leaves wet.
Location – If you have the space and get the appropriate amount of light, bathrooms are great locations for plants since they are the most humid room in your home.