Read the full tutorial on optimal grow light distance from plants. Color spectrum – yellow/orange/red colored grow lights (like the light from HPS bulbs or “soft white” colored CFLs/fluorescents) tend to produce the densest buds. Their color mimics the reddish light from the autumn sun. However bright light in any spectrum will produce good bud as long as there’s enough brightness. HPS lights produce intense light levels and give off a color spectrum that is ideal for big yields and very dense buds.
HPS grow lights are one of the most efficient grow lights available today as far as electricity used for density/yields produced (even more efficient than most LED grow lights). They’re actually relatively cheap to start with, they’re just the right color spectrum for optimal flowering, and they’re more standardized and intuitive to use than many other types of grow lights. Learn more about finding the right size HPS for your space. Some growers use Metal Halide and other more “blue” colored lights for the flowering stage, and still produce good results. In fact some growers prefer MH lights for budding (even though yields are lower) because they believe the light spectrum increases trichome/resin production and overall potency. There is still testing going, but the results look especially promising for CMH / LEC grow lights, a variant of MH lights that uses a ceramic arc tube (very similar to what’s used in HPS bulbs) to increase the brightness. However, even with these improvements, CMH grow lights are still significantly less bright than HPS grow lights (CMH: 90-105 lumens/watt vs HPS: 105-150 lumens/watt).
No matter which grow lights you’re using… Make sure you’re using a good reflector and reflective walls to get as much light as possible to your plants Keep lights close to the top of your canopy without increasing heat to unsuitable levels or light-burning plants. It’s important to find out how far your grow lights should be for optimum growth. Make sure that all parts of the plant (and especially bud sites) are bathed in bright light – any buds in a shadowy part of the plant won’t become dense! 2.) Grow a strain that tends to produce dense buds. Genetics play a huge role in how your cannabis plants grow, including the appearance, smell and taste of their buds. Indica-dominant strains tend to produce more dense buds (though not always of course). The indica-leaning buds pictured to the right are incredibly dense and were grown under intense light, but the majority of strains could never achieve this density no matter what you do as a grower. To a certain degree, density is determined by strain. Some sativa-leaning strains tend to produce less dense buds, but also provide a cerebral “daytime” effect that many growers love. Sativa-dominant strains can still be high-yielding so you may end up with very long buds as opposed to small thick nuggets like with some indica-leaning strains. Seeing different grows featuring a strain will help give you an idea of what the buds of that particular strain tend to look like. There are sometimes different versions of strains by different breeders. You can often find several versions of very popular strains, and each version can grow wildly different from each other and which produce different results. “White Widow” from one breeder may be completely different that “White Widow” by another breeder. So when researching strains, always pay attention to the breeder in addition to the strain name. How to Research a Marijuana Strain (or read the full tutorial here) Make a list of a few possible strains to grow – If you don’t already have an idea about which strain you want to grow, it helps to start by narrowing down your list of possible strains. When I’m researching for a new grow, I usually start with a big seed bank,since they give you lots of helpful information about each strains. These big seed sources usually have a “strain selector” option that lets you put in the specific features you’re looking for and get a list of results. I use Seedsman because they only carry seeds by trusted breeders. Search for a grow journal with pictures of your strain during the grow process – Type “STRAIN-NAME grow” into Google.com and look at the regular results plus the Google image results. When looking at image results, it’s important to click through to the page instead of just looking at the image so you can learn more. These steps may give you good leads toward finding a grow journal featuring your strain, but not always. Remember to also pay attention to which breeder the grower got their strain from. Search for the strain name on Youtube – you may possibly find people who may have grown the strain and documented their grow with video. Video is a great way to give you an idea of your strain might look like in the flowering stage, and lots of growers post full video grow journals on Youtube.
Seedfinder – I like the site http://en.seedfinder.eu/ for strain research. It is one of the best ways to find out the genealogy and ancestry of a strain by a particular breeder. It has growing reviews and pictures for some strains which is really helpful, but that can be hit or miss since many strains are missing any type of grower feedback. Some of the reviews are in German or other languages. You can translate almost any language into English by copying and pasting it here: https://translate.google.com/ One last thing to keep in mind… Looks are important to many growers, and looks are part of the whole experience when using cannabis.
…But when it comes down to choosing the strain, I recommend to first choose strains that produce the effects you like as opposed to thinking only about density or looks. Some strains may not produce buds that look as dense as what you see in magazines and online, but will give you exactly the effects you are looking for.