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

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

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