2026 SF G5000 led

Hi dudebush, Noone will be able to tell you your PPFD, it might looks like you given us the data a person needs, but you'll need a PAR meter to be sure. SF has the 5-in-1 Sensor you could use

A light meter can help.. but more useful to take a reading after you find a sweet spot, then match that reading in future. e.g. you start at the suggested 18" and 36% power, then based on how the plant grows you adjust further for the proper internode length of new growth etc etc.. ensure it's not too much and not too little etc etc... Then take a measurement at the top of the canopy in center. You can skil the trial and error next time by matching that value. Even a Klux measurement would be sufficient. That's also sufficient for determining proportional intensities (center reading vs edge or corner). Klux does not measure PPF, but it is proportional relative to any "1" light. so, a klux reading 50% of the center reading is also 50% of the PPF reading. There may be seasonal differences... Temp, RH, VPD, ambient co2 all impact how much light a plant will handle. The growth you see is the culmination of all those factors. Healthy and strong growth = right amount of DLI relative to environmental variables. Read up on Daily light integral, if you don't understnad the vocabulary. You don't need to memorize the math if you understand the gist of it. PPF vs PPFD are two different things. Any single reading is PPF. PPFD is light across an area (umol/s PAR per m^2... PPF is simply umol/s PAR) PPFD and hours is what you reference on a DLI table. DLI is an apples to apples measurement of light applied to the plants regardless of size of garden or hours of light) DLI is the best way to understand light provided to a plant.

18h operation, 18" hanging distance, 36% power 12h operation, 18" hanging distance, 54% power If it's an autoflower... just stick with 18/6 schedule, obviously. Why: Bwahah 1400 PPF in a 3x3? You have way too much light for .84m^2. So, this depends on hours of operation... rate x time = energy applied.... 18hours only needs ~600 PPFD for ~38.9DLI. This is a good starting point. You may still need some finer adjustments but it will get you close. Local variables makes this a moving target. What is right for you will almost certainly be slightly different for someone else, unless both people have the same lab-precision control over the environment. 600 / 1400 x .84m^2 = 36% So 18" at 36% in a 3x3 should be a good starting point. For 12 hour operation we can take a shortcut since we already figured out 18 hour operation. 43% x 1.5 = 54% power at same 18-20" hanging distance. (inversely proportional to hours of operation, all other factors the same - 18/12 or 3/2 or 150% being the factor applied) The exact hanging distance you chose should be as much if not more about proper coverage minimizing difference between hotspot in middle and edges without sacrificing overall PPFD... I'm assuming this light is barely fitting into a 3x3, so you probably have excellent end to end coverage without a longer distance for light to spread out. Maybe, 16" is better for this context.. just knock off a few percent from the above suggestions if you go that route. Adds a little more trial and error to the process, but certainly doable. Don't get too close. There is benefit to stronger light from further away due to how quickly light spreads out and loses intensity (inverse square law). So, higher power and greater distances providign same DLI will have better light penetration --- the concept behind this is same reason why outdoor plants have no difference in growth if exposed to light at bottom or top (ignoring shielded buds)... compared to millions of miles of distance to the sun, it's zero measurable difference from the top of the plant to the bottom in that context, unlike artificial lighting indoors. The important thing is - whatever you figure out for vege phase, is an easy adjustment for flower phase... whatever you settle on, it'll need 150% more over 12 hours than it could handle over 18h. The same DLI will result. If you use different hours of operation, adjust the math accordingly. e.g. 20h to 12h is 175% more power needed (20/12). There is absolutely no reason for you to use more than 18h in vege as your light is way overpowered. This also assumes the specs on https://www.spider-farmer.com/products/spider-farmer-g5000-led-grow-light/ are accurate. What you have is a light built for 15-16sq ft and using it in a 9sq ft space... this is way too much light for a 3x3.

Seedling 24–30 inches 30%–40% Veg 18-24 inches at 50-70% for 18 hours. Early 15-18 inches at 70% Late 12-18 inches at 80% Last week 50%

Best way is to use a light meter to hit your desired PPFD/DLI. I use the Photone app on my phone, works great. It used to be a free app, but I have heard they started charging for certain features. Have fun!