Gardening

No yard? No problem. A gardening expert offers tips for indoor plants.

How much light do you need? When should you water? Plus, the 411 on growing tomatoes inside.

By Vivi Smilgius

June 20, 2023

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Summer kicks off tomorrow, and the flowers are blooming, but if you’re living without a yard, don’t feel left out. If you’ve got a green thumb or want to enjoy the many health benefits of indoor plants, you can.

Bonnie Power, a Speakers Bureau expert on indoor plants at the Massachusetts Master Gardener Association, said a good indoor plant must be able to handle a less-than-optimal environment.

“The best indoor plants are those that can tolerate poor lighting and dry conditions,” Power said. “The biggest problem for indoor plants is lack of enough light, and right behind that is poor watering habits.”

Below are Power’s tips on growing at home, from light to moisture to which plants to grow and which ones to avoid.

Which 🌿🌿🌿🌿 should you grow?

Power said Begonias and African violets do well indoors, and each genus has a variety of species. She also got tropical hibiscus, jasmine, and Mandevilla to bloom in the winter, she said — though she noted she has a sunroom with floor-to-ceiling windows.

While she reported success with flowering plants, Power said, she’s been unlucky growing edible ones — with the exception of Meyer lemons — indoors, due to a lack of light.

Most edible plants require greenhouse-like conditions that are difficult and demanding to replicate indoors, she said, but herbs, tomatoes, and peppers do well on a deck, if you’ve got one.

How much 💡💡💡 do you need?

To find out how much light is available in your home, Power recommended using a handheld photometer or downloading a light meter app like LUX or Photone. After you know how much light is available in your home, you can choose plants that can live there.

Light is measured in foot-candles, Power noted, and you can match the number of foot-candles in your apartment to the number a plant requires to grow.

Power said it’s possible to grow plants in apartment lighting, but many will only survive, not thrive. She suggested using grow lights or daylight LED bulbs to encourage foliage growth.

She also recommended that plants be placed within 3 feet of a light source.

“Plants are not decorations,” Power said. “Too often, people place plants where they are good decoratively, but too far from the light or where the light doesn’t reach.”

When should you 💦💦💦 them?

There is no set water requirement for each plant, Power said. Instead, it depends on the size of the pot, the indoor humidity, and the type of soil. For soil, Powers recommended a mix of half potting soil and half perlite, pumice, chopped bark, chicken grit, coarse sand, or fine aquarium gravel.

Water your plants when the soil is dry, and do it “deeply, not little sips,” Power said. Avoid lining the bottom of your pots with rocks or other material, and buy pots with drainage to allow water to flow through and out.

Indoor plants also need humidity, especially in the winter when the heat is on, Power said. Despite public misconceptions, misting and pebble trays do not change humidity, she said — only a humidifier can.

How much 💡 and 💦 does a specific 🌱 need?

The following table shows the light, water, and fertilization requirements of indoor plants, as well as how large the plants will be at peak size. Units of measurement are explained below.

Units of measurement, explained

Light Levels 

Water Requirements

Fertility