Full-Spectrum Lamps Emit All Colors of Light

March 13, 2019

Full-spectrum grow lamps, whether they skew warm or cool, will emit some percentage of all colors of light within the PAR range. Cool full-spectrum lamps will still emit some red and yellow light, but less of it. Warm full-spectrum lamps will still emit some blue and green light, but less of it.

Seedlings growing under full-spectrum fluorescent lamps.
PC: Homestead Gardens

I can grow young tomato transplants in an open space under a large eight-lamp fluorescent fixture filled with cool-spectrum lamps. As plants grow, I replace half the cool-spectrum lamps with some warm-spectrum fluorescent tubes when I want to trigger more flowering.

Gardening Under Lights Book

Powdery Mildew on Indoor Plants

March 12, 2019

Powdery mildew is a fungal disease with fuzzy white growth. It spreads quickly, covering foliage and blocking photosynthesis, causing leaves to yellow and drop. Zinnia are particularly susceptible to powdery mildew.

Powdery mildew on zinnia leaves.
PC: Leslie F. Halleck

Cull the herd if you have a pest or disease outbreak among your indoor plants. Consider removing any heavily infested plants in order to limit the impact on less affected plants.

Gardening Under Lights Book

Tiny Seedlings Need Bright Light

March 11, 2019

Once germinated, tiny seedlings need to be close to a bright light source so they don’t stretch. If the light is further away, young sprouts can quickly stretch beyond their ability to remain intact.

PC: Leslie F. Halleck

Light from a windowsill alone won't be enough to support young seedlings. They'll stretch and topple over. Best to add a grow light, 3-4 inches above seedlings as they germinate.

Gardening Under Lights Book

Fiddleleaf Fig Care

March 10, 2019

Fiddle-leaf figs, one of the most popular houseplants today, are actually large trees in their natural environment. Make sure to provide a container that has at least a 5-gallon volume, but you may need to increase the size as your fiddle-leaf fig plant matures.

There is no cooler houseplant than the fiddle-leaf fig.
PC: Leslie F. Halleck

These plants need to be watered once every week. If yours is 5 to 7 feet tall, give it about a quart (1 liter) of water. If yours is larger, it will need about a gallon (4 liters). Make sure the soil always remains slightly moist.

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

Grow Kale

March 9, 2019

Kale, or leaf cabbage, refers to several varieties within the species Brassica oleracea. Many are beautiful ornamental kales that can serve dual purpose in an edible landscape, offering a variety of foliage colors and textures.

PC: Ball Horticultural Company

Want to grow kale indoors? Keep in a cool location and use lower-heat grow lights such as LEDs, HOT5 Fluorescents or CFLs, versus HID lamps. You can grow kale and related leafy crops under shorter light periods of 11-13 hours to discourage bolting, or grow them under longer photoperiods of 14 to 16 hours to boost production- but you'll need to harvest more quickly.

Grow Lamp Distance From Plants

March 8, 2019

You can place cooler-running lamps, such as fluorescent and LED, much closer to your plants, at about 6 inches, or the equivalent of a 150-watt HPS lamp.

PC: Leslie F. Halleck

These peppers and tomatoes are growing several feet below a 315-watt CMH lamp – it’s the perfect distance for this growing environment and these plants. Everyone is happy.

Gardening Under Lights Book

Ladybug Larvae Eat Whiteflies on Citrus

March 7, 2019

Ladybug larvae are ferocious predators of pests such as aphids and whiteflies. Somehow ladybugs managed to find their way indoors when my citrus plants have whiteflies.

PC: Leslie F. Halleck

If you are pesticide free, you can employ beneficial insects in both outdoor and indoor operations. Do not expect beneficial insects to persist long term in an indoor enclosed space; eventually their food and water will run out and they will die off.

Gardening Under Lights Book

Tips for Growing Oregano

March 6, 2019

Oregano is a hardy and easy-to-grow perennial herb. It provides the signature flavor for many Italian and Mediterranean dishes.

PC: Ball Horticultural Company

You can plant perennial oregano any time during your outdoor growing season, and it will remain evergreen in warm climates. In cold climates, foliage may die back, but plants will return from the roots. You can grow oregano in containers indoors year-round in bright light, with supplemental light from grow lamps. Keep flowers pinched and harvest foliage regularly to keep plant rejuvenated.

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

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