Some Seeds Need Red Light to Germinate

March 16, 2019

Some plant seeds do not germinate until they are exposed to red light. If you have ever tried to grow lettuce from seed, only to be disappointed when the seeds did not sprout, you most likely covered the seeds with soil and blocked them from the light.

Lettuce seeds require light to germinate.
PC: Leslie F. Halleck

Check the seed pack to see if your seeds need some exposure to light to germinate before you plant them.

Gardening Under Lights Book


Coir for Seed Starting

March 15, 2019

Coir is excellent for growing seedlings and mixing into the growing media for larger plants. You can use coir alone or in combination with other ingredients, or even as a hydroponic substrate.

PC: Sunlight Supply, Inc.

Coir also holds moisture well for an extended period while maintaining a porous structure that drains well. I like to sprinkle a little coir on top of the soil when I'm germinating seeds, as it helps hold just the right amount of moisture for seeds to germinate successfully.

Gardening Under Lights Book


Grow Dwarf Squash Indoors

March 14, 2019

Want to grow squash plants indoors? Standard squash plants are vines - and they can get BIG - reaching 15 to 20 feet long. Dwarf bush squash, on the other hand, will stay in the 3- to 5-foot range and are easy to keep in containers indoors.

PC: Leslie F. Halleck

It's always best to direct seed squash outdoors or into final container you plan to use indoors indoors. While many garden centers will offer transplants of squash plants and their relatives, these plants do not transplant well and growth is often stunted after transplanting.

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


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.


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