Led Grow Lights,Auto ON/Off Timer 40W 40 LED Shengsite Dual Head Growing Light for Indoor Garden Greenhouse Plants,3/9/12H Memory Timing,5 Dimmable Levels

If you follow (or read) my Amazon reviews you can see that I've been running numerous agricultural/botanical science experiments for the last few years. I have literally purchased almost every single "LED Grow Light" on Amazon. I continue to purchase them and test them as others request. I have tested all of the 300-600w, all the 36w, 48w, and 60w "LED grow light bulbs", all the way up to to the majority of the 600-2000W LED panels. I have been been running everything in two laboratories with controlled environments and controlled conditions. I use an Apogee Quantum Par meter, and several other sensors as testing redundancies. The plants in the (recent) experiments are: Basil (normal and purple), Bunching Onions, Mint, Arugula, Okra, Tomatoes, Strawberries (several varieties) , Dill, Lettuce (several varieties), Lavender, tissue cultures of California Redwoods, Marijuana (Indica and Sativa strain), tissue cultures of peas. Nutrient delivery is computer controlled and precisely monitored by a Growlink system and an AutoGrow Intellidose system (I'm super redundant). Over the last 18 months I ran experiments in DWC hydroponics, STERILE, DWC "Bennie", Aeroponics, Ebb and flow, ebb and drain, Kratky method, and full aquaponic systems. DWC hydro with elevated co2 consistently produces the largest yields with highest quality in the least time. It is important to understand your plant's requirements when choosing a grow light. The plant in my video review is a Tradescantia Zebrina (species originally from Mexico) aka "Red Hill". There are many varieties of this species. Some grow only green, some grow green with hints or purple, and some like the one I found, grows vibrantly purple and pink with a glittery shimmer. The Red Hill prefers partial sun. I've experimented with this species quite a bit. Boosting c02 and giving it elevated nutrients doesn't cause this plant to bolt or increase the growth rate, it seems to do best with limited exposure (4-5 hours a day, never bothered to monitor the DLI) to lighting around 70-150 μmols. I mention all this because even though I have hundreds of grow lights to choose from, most of them are not made for early stage growth or for supplemental assistance, or simply they are (not positively) overqualified, pumping out too much heat or too much intensity. Utilizing a stronger light for less hours becomes a scheduling and photosynthetic mess with plants in the local area. Most LED grow lights simply don't allow you add a dimmer to them. So for all these dilemmas, the Shengsite 20w gooseneck grow light with built in timer, is a perfect solution. The Shengsite 20w gooseneck LED grow light is built well and using slightly better components than the 20w and 40w gooseneck grow lights that I see coming out of US manufacturers. Specifically the Shengsite 20w uses bead LEDs (versus bendable IP65 RGB LEDS), an aluminum enclosure around the lights (versus plastic like the US made ones), robust bending arms (compared to the flimsy arms that don't hold positions), and the option to run off USB or standard plug (most US manufactured ones that are not simply whitelabeling an Alibaba grow light assume you want to use a standard plug). I prefer USB's for these specific style of grow lights since I have several supplemental lights and it is much easier to plug in 10 USB's to a 15 to 1 USB hub, than to run wires all over the place. The Shengsite 20w gooseneck LED grow light comes with a built in timer, which conveniently remembers the time you turned it on, and will continue to turn on at that same time each day to the timer length (3hr, 9hr, 12hr) you selected. The light has almost zero thermal footprint. In other words, it runs extremely cool. Expect it to be slightly a few degrees higher than your room's ambient temperature. You can safely touch your plants foliage directly to the LED (as long as the plant can sustain the max μmols). Surface temp probe reads 79f on the metal backside, after it had been on 24hrs straight in the laboratory with an ambient set temp of 82f. Leaving this light on the maximum setting and on the (built in) 12hr on timer schedule, this light cost me $0.23 a month to run. I actually think that is too high and that my sensor isn't able to track this low of power consumption accurately. Either way...that's peanuts anywhere you live. Any gripes? Sure I have one minor one, it is a personal preference so I won't ding a star...I really wish it had a 18hr setting on the timer. Some plants benefit from more than 14hrs of daily light in order to continually remain in vegetative state. 18 hours would cover that. Also it would be wonderful to have a couple LED bars that indicate how much time is left on your timer. Currently it blinks one, two, or three times to indicate which timer setting you have chosen. The light can be dimmed by holding the +/- button, however, for the test I left the light at Maximum.Using an Apogee Full spectrum smart Quantum sensor, the SQ-520: 561 μmols at 3cm (practically touching plant, but safe as the light emits very low heat) 220 micro moles at 1 inch 160 micro moles at 4 inches 70 micro moles at 8 inches 45 micro moles at 12 inches NA for anything beyond that. You can use the following calculation to determine the hourly PAR. Substitute your actual instantaneous PAR measurement for the 'XX µmol’' below: Hourly PAR= (XX µmol / m^2s) ( 60s / 1min) (60min / 1hr) (1 mol / 1 x 10^6µmol) = 0.36 mol / m^hour In case anyone isn't tracking along, here are some definitions: Humans use Lumens. Don't measure a lights effectiveness by it's luminosity. For example the FEIT 300watt LED $40 bulb is extremely bright and can light up a .25 acre backyard, it's marketed as "stadium lighting replacements", high lumen rating, however it doesn't grow anything well. Plants use PAR, PAR stands for photo-synthetically active radiation (PAR). PAR is NOT a measurement or “metric” like feet, inches or kilos. Rather, it defines the type of light needed to support photosynthesis. PPFD - Photosynthetic Photon Flux Density (PPFD), measures the amount of PAR that actually arrives at the plant, or as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. Photon Efficiency....Photon Efficiency refers to how efficient a horticulture lighting system is at converting electrical energy into photons of PAR. Many horticulture lighting manufacturers use total electrical watts or watts per square foot as a metric to describe light intensity. However, these metrics really don’t tell you anything since watts are a measurement describing electrical input, not light output. Oh and I mention Micromoles quite a bit (looks like this µmol ) – Let me explain...Intensity of a light is measured over a fixed area to understand the ability of a light to cover an area with that intensity (coverage). Micromoles of photons per square meter per second (µmol/m2/s) measures the intensity by taking measurements in a consistent 4 x 4 grid, measures the coverage of that intensity–commonly known as PPFD per 4 x 4 grid. Rather than measuring light intensity by lumens per watt with a lux meter, growers should use a quantum PAR meter to measure the micromoles of photons per square meter per second (µmol/m2/s) at the canopy level. To best calculate PAR light intensity coverage using PAR mapping 4 x 4 grids, be sure and measure at various heights. Spot readings (PPF) metrics are misleading. Growers use PPFD per square meter to accurately measure intensity and coverage of that intensity. What does this all mean? All plants require a specific level of μmols to grow properly. The sun puts out anywhere from 0 to infinite (hey you can technically put a sensor next to it) but on Earth at most common elevations, you're looking at around 700-2600 μmols, higher elevation and clearer sky the higher the measurement. Add some clouds and a few trees and the natural movement of the sun across the sky and you're probably getting somewhere around 800-1400 μmols during the brightest and most intense time of the day. But the sun isn't a light, it slowly rises increasing in brightness and intensity before reaching a peak then beginning a journey of decreasing in brightness and intensity. The measurement of how much sunlight they receive over a single day is referred to as the daily light integral (DLI). More specifically DLI is a measure of the amount of light received in a single day in a particular area. Starting out seeds under more μmols increases the sprout rate. However if you were to put a 1000w LED grow light 6-12'' over seedlings, the thermal intensity emitted from the LED's themselves, would most likely cook the seeds. So having more power isn't the best solution in all scenarios. Could you just mount the 1000w LED to the ceiling and spread the intensity over a huge area? Sure but again...if you're growing a few trays of microgreens you are wasting an absurd amount of power to accomplish so little while also dumping a lot of heat into the grow area. I'm basically saying choose the right tool for the job. If you're like "whoa dood, I'm just trying to grow baby tomatoes for grams and you're going Bill Nye on me", I'm simply saying: This is a well built LED by a well-known Chinese manufacturer. It is not considered a "commercial growers" light so please be realistic when rating LED grow lights. This should be considered a perfect LED for sprouting, seedlings, cuttings/clonings, microgreen trays (2 trays per light), or a perfectly flexible supplemental light for any indoor plant you love! I hope this was helpful! Thank you for taking the time to read my review, I appreciate it!

The paramount feature of this product is the ability to flex the twin or dual light heads to fit your need. New plants need the light a tad closer than normal; as the plants grow the light heads can be flexed upward to allow proper distance from the plants. The aspect I do not like is that the dual light system is a clip-on. The clip-on feature allows variability in where you can mount the light system, but it would have been better if it had a base to sit on a flat surface. A better design would be one where you begin using the light system sitting on a solid base - then allowing it to convert to a clip-on as a higher locale would be needed to raise the light as the nursery plants grow upward. Nonetheless, this system works well if you can resolve finding a clip-on place for newly emerging plants close to the table surface. Secondly, the 3, 9 or 12 hour lighting timer is oddly programmed; I had to reset this timer twice before it remained as programmed for daily lighting of young plants. I find that the 9 hour cycle of daily lighting works best for acclimating the plants toward planting in Mother Earth. This review is based on one week's use of this product.

The lights themselves work, but the timer functionality is broken somehow. I can get the 3 hour timer to work, but the 6 and 12 hour timers never stay on as long as they should. When I set the timer for 12 hours, I expect it to run for that long, and then turn off. Instead, I find the lights off after much less than 12 hours. very disappointed since my plants need the light and I need a reliable light source. Also, the lights cannot be used with an external timer since there is no definitive on/off switch, just a button that must be pressed each time the timer is turned on.

Works great, pretty flexible arms that *usually* stay in place without moving. No strong complaints after one winter of usage. However, I feel as though the LED light bulb products provide more bang for your buck, although those aren't usually dimmable and require buying a lamp. I just don't use the extra features that this provides (timer and five light levels, blue and red). Still, it got my succulent plants through winter!

My home doesn’t have a window that allows in sunlight, then I ordered this clip-on LED Grow light for my indoor garden.It gives me a starting point.This dual head desk lamp has flexible metal necks,they are sturdy to hold their position, you can maneuvered each head for the best coverage around the plant.I also really like the timer , I can set the timer auto turn on and off every day.An automatic timer makes this easy. Bright lights let my plants have strong, stocky stems that will adapt better during the dark, cold days of late winter and early spring.

I am pretty bummed because the timer on this light does not work and I threw away the box before checking. If you click the button 3 times in switches every six hours instead of 12. The lights on this product are a great color and very effective. Unfortunately, I have to manually turn the light on and off though...

I got a water garden for Christmas and felt like the sprouts were not getting enough light, so I purchased this grow light. It has a clip at the base that is perfect for clipping on a table or shelf. The arms are flexible allowing you to place them close or far away from the plants and would work on multiple locations. My favorite part is there is a timer. If you use the timer you can set it and forget it! Great for indoor growing during these short winter months!

I purchased 4 of these to help my succulents. I had purchased a cheaper light about a year ago and the majority of my succulents got stretched out so I know they didn't work well. So far so good, these lights are definitely supplying the right amount of sun they need. They are super easy to use, especially the timer which is awesome. They are great quality, love the bendable necks, that really makes it easy to place the lights exactly where I want it. Overall I'm super happy with these!!