
Ed Rosenthal Blog
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Ed Rosenthal is a leading cannabis horticulture authority, author, educator, social activist, and legalization pioneer.
Ed Rosenthal Blog
1w ago
Welcome to Hydroponics 101: Indoor Cannabis Growing Basics Today, we’re diving into the fundamentals of hydroponic cannabis cultivation, covering pH levels, nutrients, and PPM (parts per million) —essential knowledge for any grower looking to maximize yields in an indoor hydro setup. Let’s get started with the basics of hydroponic cannabis growing ..read more
Ed Rosenthal Blog
1M ago
Choosing the Right Cannabis Grow Tent Setting up a grow tent for indoor cultivation is a great way to maximize control over the growing environment. A well-organized tent optimizes plant growth, ensures privacy, and streamlines maintenance ..read more
Ed Rosenthal Blog
1M ago
Welcome to the 2025 Indoor Growing Class! This course will guide you through every step of indoor gardening. We’ll start at the very beginning with germination, laying the foundation for healthy, thriving plants.  ..read more
Ed Rosenthal Blog
3M ago
Looking to build your own seed separator? This DIY guide will help you construct a custom seed separator, perfect for cleaning various crops like hemp, corn, beans, and cannabis. Using Purple Caper Seeds' blueprint, you’ll create a reliable seed cleaner that works effectively with standard shop vacuums and is tuned for maximum efficiency in handling cannabis seeds ..read more
Ed Rosenthal Blog
11M ago
With planting season upon us, I want to use this Blog to highlight our friend Christian Petke’s effective germination technique. In his last trial of the method, he had over 98% success. In three days, you’ll have healthy seedlings sure to sprout big buds. Enjoy.
Ed
Day 1 - Sanitize, soak, and save your notes
There are many different methods for seed germination. For Christian’s technique, you’ll need the following supplies:
Weekly pill organizer
Paper towel
Distilled water
3% Hydrogen peroxide
Cannabis seeds from a reputable supplier like Purple Caper
Heating Mat with Adjustable T ..read more
Ed Rosenthal Blog
1y ago
Hello my friends,
As someone privileged to explore an array of new products within the cannabis field, I've come across innovations that truly disrupt the status quo every so often.
One aspect that has long begged for evolution is the curing process. The traditional 'burping' approach, though effective to an extent, leaves much to be desired in terms of efficiency, safety, and ease of use.
Enter TerpLoc, a paradigm-shifting solution that transcends the limitations of conventional curing. This innovative product has caught my attention for its elegant and incredibly effective approach to ..read more
Ed Rosenthal Blog
1y ago
The photo above: You might not see the caterpillar because it is already burrowed deep into the flower, but you can spot its feces. If you have caterpillars botrytis is not far behind. It grows on the feces and the areas where the caterpillar damaged the plant. It pays to be vigilant! Photo by Christian Petke
In July, my newsletters discussed battling plant enemies like bugs and mold. But there’s another cannabis enemy that may affect your garden later in the season: caterpillars.
Caterpillars are the larval stage of butterflies and moths. Caterpillars are often the same color as leaves ..read more
Ed Rosenthal Blog
1y ago
Signs of heat stress - The Photo above: By Dutch Passion Seed Company
Cannabis plants are hardy and survive outdoors in a wide range of temperatures. As the temperature rises past 85°F (30°C), photosynthesis slows until it stops between 90–95°F (32–35°C). At this point, plants go into preservation mode; photosynthesis stops as the plants spend energy acquiring water through the roots and transpiring it through the stomata to keep cool.
For short periods, most cultivars withstand weather, up to 120°F (49°C), as long as they have adequate supplies of water and a large enough root system ..read more
Ed Rosenthal Blog
1y ago
Lucas Wiseup has done some extensive traveling in the hash-producing regions of the world and I am delighted to present him as today’s guest blogger. He has agreed to do a 4 part Series on Cannabis Cultivation and Processing in Afghanistan and I look forward to sharing these with you. His photographs of the people and land are timeless images of a culture now suppressed. I encourage you to take a look at his book
"Afghanistan, Fortress of Cannabis," available at www.wiseup-photo.com
-Ed
Travel Tales from the Heart of Afghan cannabis culture
In 2018, I stayed for two months in the city of Mazar ..read more
Ed Rosenthal Blog
1y ago
Medium Size Indoor Garden / Photo by David Downs
Before you add another light, add C02.
— Ed Rosenthal
The importance of carbon dioxide cannot be understated in the cultivation process. Having robust C02 levels ensures optimal plant health and maximum yield.
Plants create sugars using the process of photosynthesis which is powered by light.
The light is used to separate water’s two elements oxygen and hydrogen. The oxygen floats into the air. The Oxygen is combined with CO2 to create sugar, which is used as food to power metabolism and to grow.
As noted in the Cannabis Grower’s Handbook: Ca ..read more