Grow Lights: What are Lumens?

March 24, 2019

The measurement of lumens tells you how much light you can expect to see from a given lamp, or the total amount of light output. Lumens per watt (LPW) is used to measure the efficiency of a lamp, or how much electricity a lamp converts into light versus heat.

Most grow lamps will provide you with a Lumens output, a measure of visual brightness.
PC: Leslie F. Halleck

Remember, plants and people see and use light differently. A light source may seem bright to your eye, but that doesn’t mean it’s better for plants.

Gardening Under Lights Book

Aphids on Peppers

March 23, 2019

When grown outdoors, peppers are a tough and pest resistant crop. Not much likes to munch on pepper foliage or the hot fruit. However, once you grow peppers indoors you'll find there are some pests that can be an issue. Aphids are a common on new pepper plant foliage when grown indoors and on pepper seedlings you're growing indoors to plant outdoors. .

PC: Leslie F. Halleck

Aphids can be difficult to treat as they are persistent on indoor crops. Best methods for control include: sticky traps, horticultural oils, and spinosad sprays.

Gardening Under Lights Book

Why Aren't My Tomatoes Ripening?

March 22, 2019

Are you growing tomatoes indoors, or growing them outdoors in a cool climate? Gardeners in cool climates often struggle to get tomatoes to ripen before temperatures get too cold.

PC: Leslie F. Halleck

Tomatoes grow well with daytime temperatures between 70°F and 90°F (21–32°C) and a drop night temperatures to between 55°F and 75°F (13–24°C). Night temperatures above 85°F (29°C) can cause heat delay, where plants don’t set fruit. Cooler temperatures will slow or stop ripening.

If you live in a warm climate, and planted fall tomatoes, you might also struggle to get them to ripen once night temperatures get too cool in fall.

If you're growing tomatoes in your outdoor garden, but just can't get them to ripen, you're going to need to warm it up! If you haven't figured out how to control the weather (slacker), then consider bringing the plants indoors, under grow lights, to provide warmer temperatures and fruit ripening.

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

Grow Cuttings in an Automatic Propagator

March 21, 2019

You can fill your propagator with multiple types of cuttings. Don't just limit yourself to one kind of plant. This way, you can propagate your entire garden at once!

Cuttings of salvia, tomatoes, citrus, and more in the propagator.
PC: Leslie F. Halleck

There are a number of automatic propagator, or cloning machines, available for you to root cuttings. This is an aeroponic propagator, which sprays a mist of water continuously onto the bottoms of cuttings until they form roots.

Gardening Under Lights Book

Thermoperiods for Plants in Grow Tents

March 20, 2019

A crucial temperature measurement for your plants is the difference between day and night. This change is called the thermoperiod. Plants rest at night in cooler temperatures, when photosynthesis, respiration, and transpiration slow, and recover from stress and water loss. Cooler night temperatures can also increase flower size, keep flower color vivid, and extend flower life.

If your tomato plants keep flowering, but don’t set fruit, temperature are too hot.
PC: Leslie F. Halleck

If you’re growing plants in a tighter enclosed space, such as a small closet or a sealed grow tent, pay close attention to the heat output of your lamp. Many grow tents specify that, for example, you need to air-cool the tent when using a lamp that pulls more than 600 watts. Otherwise far too much heat will build up inside your tent.

Gardening Under Lights Book

Light Photoperiods for Growing Squash Indoors

March 19, 2019

If you want to grow squash indoors with grow lighting, you're in luck! Squash will flower under a variety of photoperiods, and you can grow them successfully with anywhere from 12 to 18 hours of light; 12 to 14 hours are adequate with high-intensity lighting.

PC: Leslie F. Halleck

You will have to hand-pollinate indoor squash flowers. Squash and other cucurbits produce male and female flowers on the same plant. Male flowers typically emerge first, followed by female flowers, which have a swollen ovary (looks like a mini fruit) behind the flower.

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

Countertop Grow Lights

March 18, 2019

Many countertop lamp setups allow you to grow small edibles, such as microgreens, small lettuce transplants, small herbs you keep snipped, and seedlings you plan to transplant outdoors. They typically take up only 2 to 3 square feet of space, and they may fit under your kitchen cabinets.

I installed these cool full spectrum grow lamps with small reflectors under cabinets to support small herbs and lower light houseplants.
PC: Leslie F. Halleck

Just remember that as plants grow and reach the lamp they may burn, so harvest herbs and transplant seedlings before they get too tall.

Gardening Under Lights Book

Use a Humidity Dome to Root Cuttings

March 17, 2019

Plant cuttings need slightly higher humidity as they develop new roots. Cover all cuttings with a humidity dome to keep moisture high during rooting. Don’t overcrowd: while you have to maintain humidity around the cuttings during rooting, they also need good air circulation.

An aeroponic propagator.
PC: Leslie F. Halleck

Site cuttings away from intense or high levels of light, which could burn them. Bright light from a window or a couple of feet away from fluorescent or CFL fixtures will be sufficient until the cuttings have rooted.

Gardening Under Lights Book

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