Newer CMH lamps require less electricity to generate more usable light output, so you can use a lower-wattage lamp than you might with an HPS or an MH lamp. CMHs are thus more efficient than standard MH lamps, and they put out less heat than HPS lamps, which is a great benefit to most home growers.

With a more full-spectrum light output and a 20,000-hour life span, a CMH lamp is a quality all-around HID lighting solution for home gardeners who want to grow a variety of plants indoors without switching lamp types.

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There are 25,000-30,000 known species of orchids, and their care requirements vary. Orchids have three general categories of light needs: low (200-300 PPF), medium (300-600 PPF), and high (600-1000 PPF).

The color of orchid leaves will tell you if they are getting too much or too little light. Normal, healthy leaves should generally be a light, bright green. Leaves that become very dark generally aren’t getting enough light, while a pale yellow-green or red tint indicates plants are getting too much light.

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Beets are root vegetables that also offer edible leaves. There are many varieties of beets with a number of root colors, sizes, and flavors--a rainbow of beet options.

Direct seed beets into the garden, or into the final container you'll use to grow them indoors. Thin seedlings so that there are a couple of inches between each remaining seedling. Use a balanced granular vegetable fertilizer in the soil or growing media at seeding time. Then side-dress the beets or use a liquid fertilizer one or two more times during their growing cycle.

New BOOK! Gardening Under Lights: The Complete Guide for Indoor Growers

Have you ever wondered why plant leaves change color? Plant leaves contain several different types of pigments called Carotenoids, flavonoids, and betalins are additional support pigments— sporting shades of yellow, orange, red, pink, and purple—that also absorb small amounts of light, just like chlorophyll.

These pigments are responsible for creating different colors in plant leaves and stems. When the chlorophyll breaks down in fall, as temperatures cool, these pigments become visible. That's why you get a fall color change in your trees. This colorful begonia, that is growing under plant lights, has more of these colorful pigments which are visible all the time.

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While you could successfully grow a few species of carnivorous plants in a bright window, most need significantly more light and humidity. In fact, most carnivorous plants grow naturally in full-sun locales, so you must provide intense light indoors for your creature-capturing plants.

Light your carnivorous plants for 12 to 16 hours per day, depending on your light source and the ambient light available in your living space.

New BOOK! Gardening Under Lights: The Complete Guide for Indoor Growers

Every crop has its own optimal humidity level, which may change depending on the stage of growth. On average, a good target for plant growth is about 50 percent humidity. Plants growing in low humidity will dry out faster. When the air around a plant is dry, it creates a high vapor pressure deficit (VPD).

Plants that dry out because of low humidity in the air become more susceptible to disease. Pests like spider mites love dry conditions and will attack plants that are already stressed from a lack of moisture.

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African violets are a classic indoor houseplant. But there's nothing old fashioned about them, as far as I'm concerned. I love collecting new varieties with beautiful flowers and they make for such a great houseplant.

Gesneriads are a large family of more than 3000 tropical species that sport beautiful flowers and foliage. Many beloved blooming houseplants, such as African violets, are members of this group. Most gesneriads have similar growing needs and are perfect for indoor gardeners. Be sure to allow plants to dry between waterings, just like with many succulents. Over-watering can quickly kill them.

New BOOK! Gardening Under Lights: The Complete Guide for Indoor Growers

African Violets are great for indoor gardeners who don’t have a lot of space but want to brighten up their home with flowers. African violets appreciate medium to bright indirect sunlight, such as you might find in a southern window. Hot afternoon sun can scorch them, but low-light conditions will leave them flowerless. Add an LED or Fluorescent grow lamp to boost blooms on your African violets if you don't have enough light indoors to keep them happy.

If you want to take advantage of the efficiency of HPS lamps but don’t want to compromise on light spectrum, you can (1) look for HPS lamps with enhanced performance in the blue spectrum, which are a great compromise, or (2) supplement your HPS lamp by combining it with some blue light from an MH or an LEC lamp, cool-spectrum, narrow-spectrum blue fluorescent tube, or blue LED.

If you are growing in an open space where natural outdoor light is present, such as a greenhouse or a room with windows, you can use HPS lamps alone to supplement the light spectrum and photoperiod—although the orange visual color of the light is less than aesthetically pleasing.

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