How far should grow lights be from indoor plants?

There is no single correct distance for every fixture and plant. Start with the manufacturer's manual and compare its PPFD map with your actual canopy height. Barrina T5 bars need close placement in our review, while the Spider Farmer SF2000 requires more clearance than the reviewed 100-watt units.

How many hours a day should grow lights stay on?

Set the schedule around the plant species, growth stage, and available daylight rather than using one duration for every plant. Give plants a regular dark period instead of leaving lights on continuously. Check your light or growing-system manual for timer operation, and use plant-specific cultivation guidance for the schedule.

Are white grow lights better than purple grow lights?

For plants you look at daily, we prefer full-spectrum white because it makes inspection more comfortable and foliage easier to see naturally. That does not replace checking intensity. Choose using PPFD across your canopy at the intended distance, rather than treating the visible color as proof of adequate growing light.

What size grow light do I need for a 2x4 tent?

The Spider Farmer SF2000 is our leading reviewed choice for a 2x4-foot tent; the MARS HYDRO TSL2000 is another rectangular option. Confirm PPFD coverage at your available hanging height rather than choosing by wattage alone. Check each model's manual for clearance, ventilation, and electrical compatibility before installing it.

The best grow lights for indoor plants

The best grow lights in our reviewed list are the Spider Farmer SF1000 for 2x2-foot growing areas, Barrina T5 bars for seedling shelves, and Spider Farmer SF2000 for 2x4-foot tents.

Research-based article drawn from our 30 indoor gardening & hydroponics reviews. Updated September 2026.

Short answer

Choose the Spider Farmer SF1000 for a 2x2-foot growing area, Barrina T5 bars for seedlings and microgreens on shelves, or Spider Farmer SF2000 for a 2x4-foot tent. Match the fixture to your plants and available hanging height, then check PPFD at your actual canopy distance. Full-spectrum white light makes daily plant inspection easier than blurple.

Our picks for “best grow lights for indoor plants”

Best for a small growing area: Spider Farmer SF1000

The Spider Farmer SF1000 is our pick for vegetative growth or flowering in a 2x2-foot area. It costs $69.99 in the supplied listing and earned our score of 8.5/10. Its 100-watt board provides full-spectrum white light, allowing natural-looking daily canopy checks, with an even spread across a small footprint.

The important limit is coverage. Although the product title mentions 3x3-foot tents, our review notes that intensity falls off at the margins of that larger area. Buy it around its documented 2x2-foot strength rather than assuming the larger footprint receives equivalent light.

Before ordering, compare the manufacturer's PPFD map with the distance you can maintain above your plants. Our supplied data contain no numerical PPFD measurements, so we cannot give a verified intensity at a particular height. The heatsink can also get warm in a small tent. Check the manual for hanging clearance and installation requirements, and allow for plants growing toward the fixture.

Read the reviews: Spider Farmer SF1000 LED Grow Lights for Indoor Plants in 2x

Best for seedling shelves: Barrina T5 grow lights

The Barrina T5 four-pack is the more suitable choice for seed starting and microgreens on tiered shelves. Listed at $28.79 and scored 8.1/10, these one-foot bars offer a modular, linkable layout rather than a single board. Their 5000K full-spectrum white output is also pleasant for a growing shelf in a room you use daily.

Our review found their distribution well suited to narrow shelves, but output is modest. The bars need to sit close to the canopy to maintain useful PPFD and help prevent leggy growth. Check the manual for the recommended placement rather than borrowing hanging distances from a more powerful tent fixture.

Short bars also mean that a longer shelf may require multiple linked units. Plan the layout around the planted area, not just the shelf's outside dimensions, and follow the manual's linking limits. These are our shelf-propagation pick, not a substitute for the boards recommended here for full-cycle tent cultivation.

Read the reviews: Barrina T5 Grow Lights for Indoor Plants

Best for a 2x4-foot tent: Spider Farmer SF2000

The Spider Farmer SF2000 is our first choice for complete-cycle cultivation in a rectangular 2x4-foot tent. It earned 8.5/10 and is listed at $159.99. Its linear board is designed for that footprint, with uniform rectangular PPFD distribution noted in our review. Full-spectrum white output supports clear visual inspection, and dimming lets you adjust intensity between seedling and flowering phases.

The trade-off is installation space. This roughly 200-watt fixture requires more hanging clearance than the 100-watt units in our notes. Account for container height, mature canopy height, and fixture clearance before deciding whether your enclosure is tall enough. Check the manual for model-specific distances and ventilation requirements.

US buyers should also verify electrical compatibility before purchase: the supplied specification lists 240 volts. Do not assume compatibility with your intended outlet. Although our review describes balanced canopy coverage, it supplies no numerical PPFD map; confirm the manufacturer's readings at your planned hanging distance before buying.

Read the reviews: Spider Farmer SF2000 LED Grow Lights for Indoor Plants in 2x

Another 2x4 option, and the buying checks that matter

The MARS HYDRO TSL2000 is another rectangular 2x4-foot option, listed at $169.99 with our score of 7.8/10. It has a 300-watt rating, full-spectrum white output, dimming, and daisy-chain capability. Its elongated layout suits rectangular beds, but passive heat dissipation raises tent temperature. The supplied voltage specification is 220 volts, so US buyers should verify the exact unit's electrical requirements.

Do not choose it over the SF2000 on wattage alone. PPFD at your canopy distance is the light-output specification to prioritize: compare the center and edges of the planted area, not just one peak reading. Wattage matters for electrical load and heat, but does not establish how much useful light reaches every plant.

For plants you inspect daily, our preference is full-spectrum white over blurple. If you are also buying a hydroponic system, assess reservoir capacity separately because it affects refill frequency. These standalone lighting recommendations do not establish a watering interval; follow your system manual and monitor water use.

Read the reviews: MARS HYDRO 300W TSL2000 Led Grow Lights for Indoor Plants, Spider Farmer SF2000 LED Grow Lights for Indoor Plants in 2x

Frequently asked

How far should grow lights be from indoor plants?: There is no single correct distance for every fixture and plant. Start with the manufacturer's manual and compare its PPFD map with your actual canopy height. Barrina T5 bars need close placement in our review, while the Spider Farmer SF2000 requires more clearance than the reviewed 100-watt units.
How many hours a day should grow lights stay on?: Set the schedule around the plant species, growth stage, and available daylight rather than using one duration for every plant. Give plants a regular dark period instead of leaving lights on continuously. Check your light or growing-system manual for timer operation, and use plant-specific cultivation guidance for the schedule.
Are white grow lights better than purple grow lights?: For plants you look at daily, we prefer full-spectrum white because it makes inspection more comfortable and foliage easier to see naturally. That does not replace checking intensity. Choose using PPFD across your canopy at the intended distance, rather than treating the visible color as proof of adequate growing light.
What size grow light do I need for a 2x4 tent?: The Spider Farmer SF2000 is our leading reviewed choice for a 2x4-foot tent; the MARS HYDRO TSL2000 is another rectangular option. Confirm PPFD coverage at your available hanging height rather than choosing by wattage alone. Check each model's manual for clearance, ventilation, and electrical compatibility before installing it.