Simple lamp timers, or more sophisticated digital timers, can be used to turn your grow lamps on and off on a set lighting schedule. Timers make it easy for you to deliver the right duration of light, or photoperiod, to your plants.

A quantitative short-day plant may bloom earlier or better if it has longer nights. A quantitative long-day plant may bloom earlier or better when given shorter nights. Both plants will eventually flower, however, even if the photoperiod is not ideal.

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These cucumber plants were started from seed at the same time. The container on top was grown under a CMH lamp with a higher PPFD, while the container on the bottom was grown under a CFL with a lower PPFD. The plants grown under the higher-intensity lamp are far ahead of those grown under the lower-intensity lamp.

Typically, the higher the PPFD delivery of a grow lamp, the more expensive it is. You can run a less expensive lamp with a lower PPFD value for a longer photoperiod and rack up the same DLI that your plants need. Just be sure not to run the lamp longer than the plants can tolerate.

You can also choose a more expensive lamp with a higher PPFD and run it fewer hours to deliver the same DLI. Provide a long enough photoperiod if one is required.

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Standard citrus trees can grow 15 to 20 feet tall. For indoor gardening, it’s best to stick with dwarf types that you can maintain at 3 to 6 feet tall.

Dwarf lemon varieties for indoor growing include: 'Dwarf Meyer’, ‘Dwarf Meyer Improved’, ‘Eureka’, ‘Variegated Pink’, and ‘Ponderosa.’

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When it comes to choosing the right houseplants, it's easy to assume that if a plant is categorized as "low light" then it can survive anywhere indoors. This is not always the case, as everyone's home...and different areas throughout the home...have very different light levels. Even low-light plants, such as ferns, may need supplemental grow lighting once you retreat to darker corners of your home.

This modern LED growing fixture, that doubles as a decorative lamp, works perfect for some small ferns I keep against a windowless wall in my living room. Complete growing units like these allow you to grow types of plants you wouldn't normally be able to grow in darker areas indoors.

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

If you want to harvest young lettuce leaves, or baby greens, then you don't have to grow just one type of lettuce at a time. You can mix together different types in the same container to grow them indoors. I like to mix multiple types of lettuce to create a nice 'salad bowl'. Try ‘Lollo Rossa’, ‘Oak Leaf’, ‘Black Seeded Simpson’, and ‘Buttercrunch’ for different colors and flavors.

Grow lettuce indoors using LEDs, HOT5 Fluorescent, or CFL grow lamps, with 12-13 hour photoperiods.

For continual leaf harvesting, snip leaves from outside the central growing point, which allows new leaves to emerge from the center. If you plan to harvest an entire head, you can grow under longer photoperiods, but be sure to harvest the plant as soon as it fills out, before it bolts.

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

There are many things to take into consideration when choosing & setting up your grow tent. The size of the grow tent will dictate the amount of lighting you’ll need to provide. The entire inner surface of grow tents is highly reflective, so you will not lose light to diffusion.

Note the temperature rating of the grow tent, both for cold temperature protection and heat ventilation. You also need to look for weight ratings for the support structure. You’ll be hanging gear from the frame, so it must be able to safely hold the equipment you plan to use.

Want to grow mint indoors? If so, you're in luck. Mint is relatively easy to grow in moderate light levels. If your mint gets leggy on your windowsill, that means it needs a grow light. There are hundreds of mint varieties, but popular types include chocolate mint, orange mint, lavender mint, apple mint, and pineapple mint.

Mint grows more vigorously and produces more foliage and essential oils with longer days - but it also flowers more. You can grow under 12 to 13 hours of light from grow lights to slow flowering, or keep flowers pinched and harvest regularly under longer photoperiods of 14 to 16 hours.

You can start citrus from seeds you kept from fruit you purchased. If you start a seed from a hybrid variety of citrus, your seedlings won’t come true to variety.

You can also propagate citrus from cuttings, air-layering, and grafting. Otherwise, pick up young or mature specimens at your local nursery and pot them.

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