First time grow?

PS: That FC4000 EVO throws serious photons even at 40%. It’s not a weak light, it’s just easy to overdo it if the room’s not balanced yet. You’re doing it right keeping it low until she’s ready.

Hey growmie, week 6 veg and 40% at 20” is actually a nice cautious setup. Mars claims are always a bit aggressive, 12–18” at 75% might work later, but not this early unless you’ve got perfect temps and airflow dialed. Right now, I’d bump up to 55–60% and keep the same distance. Watch how the plant reacts for 2–3 days. If no signs of bleaching or clawing, go a bit higher from there. Slow ramp = no shock. Your diary looks solid so far, plant looks happy,no rush. Also, if it “cooked” last time at 75%, that tells you your room probably needs better temp control or more airflow before pushing that high again. Light wasn’t the only issue. You’re right to trust your gut over manufacturer numbers. They don’t grow in tents, we do.

At week 6, 40% @ 20" is quite low—you can definitely start increasing power now. Try bumping to 50–60% while keeping the distance the same. Watch how the plants respond over 2–3 days. Mars Hydro’s 75% at 12–18" is too much for seedlings, but by mid-veg or early flower, it’s where you should be heading. Slowly raise output or lower the light distance (but not both at once). Gradual ramp-up avoids light shock—and you’re in the perfect window to do it now.

Okay, here's the thing about grow lights and weed plants. You want them close enough to get plenty of light, but not so close that they get burned. A good rule of thumb is to start with the light about 12 to 18 inches away from the top of the plant. Then, you can adjust it from there based on how the plant seems to be doing. If the leaves start to look pale or yellow, that could be a sign that the light's too close. You want to see nice, healthy green leaves. Also, keep in mind that different types of grow lights put out different amounts of heat, so you might need to adjust the distance depending on what kind you're using. PAR meters are a great tool for measuring the amount of light your plants are getting. They measure the photosynthetically active radiation, which is the light that plants use for photosynthesis. This can help you figure out the best distance to keep your grow lights from your plants. The best light spectrums for growing weed are usually in the red and blue ranges. Red light is important for flowering, while blue light is important for vegetative growth. You can find grow lights that offer a full spectrum of light, or you can use separate lights for each stage of growth. Also always make sure lighting was the problem and. It something else Healthy leaves on a weed plant should be a vibrant green color and stand upright. If the leaves are drooping, curling, or turning yellow, it could be a sign of a problem. Some common issues include nutrient deficiencies, overwatering, underwatering, or pests. Healthy roots on a weed plant should be white or cream-colored and have a strong, fibrous structure. If the roots are brown, slimy, or have a foul odor, it could be a sign of root rot. Root rot is a serious problem that can kill your plant, so it's important to address it quickly. Your weed plant will tell you if it's getting too much or too little light through its leaves. If the leaves start to turn yellow or brown, or if they look burned, that's a sign of too much light. On the other hand, if the leaves are pale or stretched out, it might not be getting enough light. You'll want to adjust your grow lights accordingly to keep your plant happy and healthy.

The only way to know for sure what your dealing with is a par meter that reads umol’s don’t get a lucky meter even though there cheep they don’t work and they are not comparable If you can’t afford one then watch what the plants tell you start the light low and slowly increase lighting amount over time never make fast lighting adjist

You can also message me with anyother questions for more detailed responses since i cant ask questions this way to get a better idea of what youre working with. Best of luck!

Need a little more information to be more helpful. But my advice is to read your plants, if theyre happy then just let them be. If you want to get more technical. Download the photone app on your phone and you can figure out what the ppfd is at for your plants with whatever distance and whatever power you have your light at. I dont start increasing light intensity until the begining of flower and then around week 5 of flower, i try to increase my light up as much as possible, so long as temps allow me to do so. If your plants got cooked, it could have to do with temperature and humidity levels along with other environmental things like airflow and vpd.