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The Indoor Sun: How To Use Sunlamps For Hydroponic

The Indoor Sun: How To Use Sunlamps For Hydroponic Gardening

Hydroponic gardens are one of the best ways to grow fresh, healthy produce year-round. But these systems will only work if you can simulate the natural growing conditions found in nature. You need to build the right environment for your plants to grow by balancing humidity, temperature, CO2, air circulation, and light.

A hydroponic system sunlamp is the solution to delivering “sunlight” to your indoor plants.

Plants use light as part of their photosynthesis. They use sunlight to gain energy, utilize their nutrients, and grow and develop.

In an indoor system, you have to try to simulate the hours, intensity, and range of natural sunlight in order for the proper photosynthesis process to occur.

How can you simulate natural sunlight with an indoor garden light?

How To Choose A Garden Light

What do you need to consider when choosing a light for your indoor system?

Light Color

Natural sunlight is filled with a spectrum of colors. Artificial light bulbs don’t contain this same range, so it’s important to apply different colors of light as necessary. The most important light colors for your indoor plants are blue and red. Blue helps regulate plant growth and red stimulates flower and bud growth.

Ideally, you should provide your plants with a balance of blue and red light throughout their growth cycle. You may want to stick to a red primary light and switch it out for a blue light during the flowering phase.

The Indoor Sun: How To Use Sunlamps For Hydroponic Gardening hydroponic garden under light

Light Duration

An outdoor vegetable garden usually requires 4-6 hours of direct sunlight and 10 hours of indirect sunlight daily. You want to simulate this “photoperiod” in your tent with 14-16 hours of bright light and 10-12 hours of darkness daily.

Keep in mind that darkness is equally as important as light. Like humans and animals, plants need a rest period to refresh and revitalize.

Thus, you’ll need to make sure your lamps go off at least 10 hours every day. We recommend using a timer to automatically turn your lights on and off in accordance with your plant’s schedule.

Plant Type

Different plants naturally require different light duration or photo periods.

Short-day plants require a longer period of darkness in order to fully photosynthesize their energy. These plants usually won’t bud if exposed to over 12 hours of light per day. They are usually spring-bloomers or fall-bloomers, where the days are slightly shorter. They can include poinsettias, strawberries, cauliflower, and chrysanthemums.

Long-day plants can require up to 18 hours of sunlight in a day. These mimic the environment of summer-flowering plants, where daytime is longer. These plants include wheat, lettuce, potatoes, spinach, and turnips.

There are also a number of neutral plants, which will produce fruit no matter the type of light they’re exposed to. These include rice, eggplant, roses, and corn.

If you have a mixture of short-day and long-day plants in your grow tent, try to find a middle ground of hours for exposure, like 12-14 hours. If you want the strongest yield, though, you may want to separate these plants into different grow tents.

Light Broadness

In an outdoor environment, the sun moves through the sky and hits the plant at a variety of angles. In an indoor environment, a stationary lamp doesn’t have this same breadth of distribution. But all parts of your plant are thirsty for light.

Thus, it’s important to try to spread out the light. This will help your plants grow and thrive while avoiding direct sunlight in one spot, which can burn or damage plants.

Grow tents with a reflective interior are especially useful for this. The metallic interior will reflect the light, creating a more comprehensive and encompassing environment of light.


The light you choose will impact the environment in the grow tent or indoor room. Hot lamps can dry out the room and lower humidity when you want to keep an ideal humidity between 40% and 60%. Lamps can also heat the room and impact the ideal temperature between 68 and 75 degrees.

However, this heat can be useful in some cases. It can keep the room toasty enough for your plants to thrive, and it can reduce harmfully high humidity levels.

Keep in mind that growth tents with a reflective interior will usually heat up more than a non-reflective room, like growing your plants in the kitchen.

Balancing your lamp’s specs with the other factors of your grow tent is important to create the ideal growth environment.

The Indoor Sun: How To Use Sunlamps For Hydroponic Gardening hydroponic garden under lights

Choosing Your Hydro Lighting System

A hydroponic lighting system has four main parts. You can buy these individually or in a pack depending on the needs of your environment. The four parts are the bulb, reflector hood, remote ballast, and timer. Below we’ll go through the options for each part, so you can be equipped with the knowledge to start buying the perfect lighting system for your hydroponic plants.

1. Bulb

The bulb is the most important part of the lamp. The quality of the bulb determines the quality of light you’re feeding your plants.

There are a number of bulb options for your hydroponic lighting, including incandescent, fluorescent, LED, and HID (MH or HPS).

Incandescent bulbs:

  • Usually emit red light (only half of plant’s needs)
  • Burns hot (can create a too-dry environment)
  • Best for vegetative plants that don’t flower
  • Cheapest option

Fluorescent bulbs:

  • Primarily blue light; some offer full-spectrum (up to 94% of total spectrum)
  • Burns cooler than incandescent
  • Offers 3x more light for the same wattage of incandescent
  • Good for both flowering and vegetative growth
  • Popular for home growers
  • Inexpensive but not cheap
  • See: Agrobrite T5 Fluorescent Grow Light System

LED bulbs:

  • New but growing in popularity
  • Can simulate 5700K color temp of sunlight—nearly the entire spectrum of light
  • Gives off virtually no heat
  • Uses little power
  • Expensive, but expected to decrease in cost as popularity grows
  • See: Gro1 Green LED Light Bulb 9W

There are also two types of HID (high-intensity discharge) lights. HID lights are on the pricier side, but they’re extremely efficient and produce the best results for hydroponic gardens. These bulbs come in MH blue light and HPS red light. It’s a powerhouse when you combine these two bulbs in a dual system.

Metal Halide (MH) bulbs are blue lights that are good for most vegetables and plants. They are inexpensive and flexible, and they’re a good “all around” option. They need to be replaced at least once every two years, though they usually start to decrease in efficiency after 15 months.

High-Pressure Sodium (HPS) bulbs are primarily red, so they’re good for the flowering or fruiting stage of plants. They’re more expensive, but they can produce a strong yield if you’re growing flowers or food. These last up to five years but may need to be replaced after two.

To save on costs and energy, we recommend using MH the majority of the time and switching out for an HPS bulb during the flowering stage. A conversion lamp works well for either type of lamp, and you can switch between the two as you move through the growth stages. See our recommendation E-Papillon Double Ended Complete Fixture here.

HID bulbs tend to show the strongest and most fruitful results. However, fluorescent bulbs can work for smaller gardens and LED bulbs are growing in popularity.

See our variety of bulbs here. Common voltage is between 400W-1000W.

The Indoor Sun: How To Use Sunlamps For Hydroponic Gardening reflector hood for garden lamp

2. Reflector Hood

The reflector hood is the reflective casing around the bulb. The hood increases the effectiveness and efficiency of the bulb, creating a wider distribution of light onto the plants. This distribution allows you to use bulbs that give off less heat, saving on electricity and cooling costs.

Check out our reflectors and hoods for a variety of needs and price points.

3. Remote Ballast

The ballast is the power box that powers the light. It’s the most expensive part of the system because it supplies the majority of the power. You should buy a ballast that matches the same wattage as your bulb.

Be sure to keep the ballast off the ground to avoid any moisture damage, especially with an ebb and flow system. 

See our selection of quality ballasts here.

4. Timer

Timers are a critical part of your lighting system. Either manual or automatic, these timers will turn your lights on and off on a schedule. Manual timers are more popular because they are less likely to break. Even one hour of lost “sunlight” can impact your plant health and yield. Setting a daylight schedule will keep your plants on a natural timetable, just as if they were following the sun during the day.

We recommend using a timer and controller with multiple plugs to power multiple lights at once. See our timers and controllers here.

P.S. Always be sure to wear appropriate eye gear when working with bright artificial lights! Too much exposure could damage your eyes.

The Bottom Line

Lights are necessary to plant growth, and indoor lighting offers strong plant photosynthesis year-round regardless of time, place, or weather conditions. Choosing a hydroponic lighting system depends on the plant types, the grow tent, the environment, the bulbs, the timer, and more.

It can be a lot to balance and understand, especially if you’re new to growing.

Contact HydroPros right now for a free consultation about your plants’ light needs and system.

Together, we’ll find you the perfect system for optimal plant growth!

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