Imagine legally growing a million marijuana ultra-premium clones per year! That’s what Dan Grace and his California-based Dark Heart Nursery team are doing in their 20,000 feet of high-tech grow space hidden away in the San Francisco area.

Professional large-scale and connoisseur craft California cannabis growers assure me that Dark Heart is the biggest clone nursery in the state that offers 100% clean, strong, reliable clones from exceptionally rare strains.

Dan Grace started Dark Heart in 2007 after being a home-based cannabis grower and cannabis activist in Oakland, California. In his formative cannabis growing years, he taught himself how to build a professional grow room, including the electrical work, financed by money he and his partner Sara worked grunt jobs to put together.

This was during the golden years for California marijuana growers, before politicians gutted Dennis Peron’s Prop. 215, the nation’s first voter-approved medical marijuana law, and before Prop. 64 and the politicians’ draconian “legalization” regulatory implementation scheme created confusion and increased costs for cannabis entrepreneurs. At the time, premium retail California bud sold for $3000-4000 a pound wholesale. Grace and his partner had good reason to believe they’d soon earn a lot of money and help heal the world in the marijuana business.

The Cannabis Business Learning Curve

But the pair experienced a harsh learning curve, like many cannabis growers go through at first. Their earliest grow ops were too warm, too cold, too humid, too small. Grace says they didn’t have effective security protocols, so rippers stole their precious buds. And he was still working his grueling day job—as a landscaper—so he came home hot, sweaty, and tired from slaving away in the sun and weather, only to spend hours in his grow op fixing equipment, tending plants, fighting cannabis pests and diseases.

Grace soon realized cannabis growers are sometimes forced to work around the clock because many things can go wrong that need attention right away, and if you don’t fix grow op problems immediately, your plants can suffer and even die.

He studied mainstream industrial agriculture best practices to learn about large-scale farming, but noticed that cannabis growers are forced to overcome challenges regular farmers never face.

Some people are prejudiced against cannabis users and entrepreneurs. A percentage of  landlords, friends, investors, family, banks, and police don’t view a marijuana farmer the same way they more-favorably view a soybean farmer. This makes cannabis farming a special kind of agriculture that comes with built-in obstacles. “My goal is to produce perfect clones that make the farmer’s life easier and the crops more productive and valuable,” Grace says.

Producing the Most Reliable Marijuana Clones Ever

Grace says his experiences as a cannabis cultivator taught him why growers need reliable, high-value clones like the ones Dark Heart now produces. He’d initially sourced pathetic, infested, stunted clones for his first grow ops, and the results were awful. By networking in the thriving Oakland marijuana community, he eventually landed his first premium genetics strains: Sensi Star and Hindu Skunk.

He and his partner built a small warehouse grow op, and unfortunately experienced the dark side of the marijuana industry when thieves broke in and stole a massive crop just days away from harvest. The loss was devastating, they struggled to pay rent, and immediately started a new crop. But it too was ripped off just before harvest!

The ripoff losses focused Grace on the idea of running a clone business instead of a bud business, in part because clones are harder to steal and profit from than buds. Grace hooked up with Oaksterdam Nursery, a highly-regarded marijuana clone factory, and learned how to clone professionally. Then he went looking for rare cuttings of the most potent, interesting strains.

Today, Dark Heart is a massive boutique clone factory equipped with LED grow lights, high-tech pest and disease control, a tissue culture lab, and humidification gear that gives cuttings the humid environment they need. Dark Heart supplies dozens of California marijuana dispensaries with clone strains like their beautiful Mirage, seen below…


Fist Fights Over Cannabis Clones

Dark Heart clones are only available in California dispensaries. One San Francisco area dispensary owner told me Dark Heart clones are in ridiculously high demand. Before Dark Heart started texting “clone drop alerts” so growers know when new deliveries of Dark Heart clones come in, they’d queue up for hours and even camp out overnight to buy out Dark Heart clones as soon as they arrived. “We even saw people fighting over their clones,” the dispensary owner recalls.

Dark Heart has become the benchmark for rare, reliable clones for every level of cannabis grower. The company’s intense popularity with growers starts with their diverse, eclectic, tasty strain menu, including strains bred by Emerald Triangle insider professionals such as Humboldt Seed Company and other breeders who use marijuana genetics nobody else has. Grace says he and his team spend a lot of time building symbiotic relationships with collaborating breeders who create new strains in direct response to grower requests.

The exclusivity and mouthwatering diversity in their strain menu is accompanied by a rigorous quality control program that eliminates the many problems clones can transfer into a grow room.

What most growers don’t realize, Grace explains, is that cuttings can carry genetic defects, infections, diseases or infestations present in the motherplants. These problems include not just the obvious, visible ones you’d see if you carefully inspect clones with a magnifying glass before purchase, such as spider mites, aphids, powdery mildew, russet mites, thrips, scale, and other pests and diseases. They also include hidden problems you need advanced quality control expertise and equipment to detect, such as viruses and mutations.

Motherplants, Genetic Drift, Tissue Culture, Pests & Diseases

Managing the selection, quality, health, vigor and longevity of marijuana motherplants is a top priority for Grace. Some growers, marijuana seeds makers and clone producers keep cherished motherplants alive for many years, but Grace wants to ensure the most vital motherplants so he takes tissue culture samples from premium plants at the outset of a clone production program and uses those timeless samples to generate identical-phenotype motherplants every few months. He also uses tissue culture to make clones, which ensures 100% phenotype consistency.

Grace said there aren’t yet definitive studies that settle the question of whether degradation in motherplants and clones made from them are caused by genetic drift over time, as many growers believe. What he is sure of is the longer a motherplant is alive, the likelier it is to experience negative conditions, inputs, pests or diseases that weaken the motherplant and any cuttings taken from it.

Another problem for clone purchasers is that many clone sellers use poisons to control pests and diseases in their clone factories. Some of these poisons are covertly systemic, and growers get a nasty surprise when lab testing reveals harmful contaminants when the clones are grown out and harvested.

Dark Heart avoids these problems by using integrated pest management (IPM) and sealed grow facilities. Grace’s team wears sterile suits and gloves, just like if they were working in a microchip manufacturing clean room. They isolate the growing areas from unfiltered outside air and any other vectors that could transfer pests, fungi, mold, mildew or contaminants into the grow spaces.

The Dark Heart team does constant monitoring of all plants and grow spaces using pest traps and visual examination. As a preventive blockade, or if pests are found in any quantity, the team uses predatory insects to knock back the invaders. Before any clone leaves the facility for sale, it’s rigorously hand-inspected and treated. If a clone can’t be guaranteed as 100% free of pests and pathogens, it’s discarded, Grace says.

Grace says the cannabis industry is way behind the Big Ag industry when it comes to understanding and fighting pathogens and pests. Crops like soy, corn, rice, alfalfa, fruits and vegetables have been studied and bred for decades to be resistant to the specific pests and pathogens that most damage them. This hasn’t yet been done for cannabis, Grace notes, but he takes special pride in being the only clone nursery to have eliminated PCIA (putative cannabis infectious agents) that reside inside motherplants and transfer into cuttings.

The Strongest Marijuana Clones Ever

Another problem many growers experience when making clones or buying them is that tender, fragile, and poorly-rooted cuttings are placed under regular grow lights, where they struggle because they don’t have the root mass or metabolism to thrive outside the humid environments cuttings are usually started in.

Grace solves this problem by growing his clones longer than most clone sellers do, so they’re at least 20% larger and better-developed than clones from other sellers. Dark Heart clones are sold fully-rooted in rockwool, with well-established metabolic, foliage and root mass foundations that allow them to be more-quickly placed under LED or high intensity discharge (HID) grow lights, as well as fed a fairly aggressive nutrients program.

“Dark Heart clones are faster out of the gate and healthier than regular clones,” Grace says, “so they’re ready for flowering sooner. This results in more harvests per year, and less expense per crop.”

Introducing Feminized Seedlings!

Another Dark Heart innovation is feminized seedlings. Some growers prefer to grow from seed because they want phenotypic variation for breeding and motherplant selection, and because they believe seed plants are more rugged and productive than clone plants. Grace has partnered with Purple City Genetics, who currently provide Dark Heart nearly two dozen OG Kush variants as feminized seedling strains.

As with Dark Heart clones, the seedlings aren’t offered for sale until they have well-established root systems. Grace says feminized seedlings are particularly popular with large-scale greenhouse and outdoor marijuana growers who benefit from bulk discounts.

One of the biggest let-downs I’ve experienced buying commercial clones is that they were mislabeled. I’d buy “Kush” cuttings that turned out to be some unknown Sativa strain, or a Blue Dream that grew out to be Girl Scout Cookies.

I asked Grace how his team can be sure—when growing a million clones of dozens of strains per year—that they’re properly tracking and labeling each baby. Grace says that his company’s rock-solid cutting labeling protocols start with its employees, who are very familiar with the look and smell of Dark Heart strains, to the extent that most employees can identify a cutting’s genetics by looking at and smelling it. It helps that Dark Heart has very tight control over phenotype consistency—clones from a particular strain will all grow out nearly 100% identical to each other.

When clones are being moved or when cuttings are being taken from motherplants, only one strain at a time is handled. This prevents crossover mistakes in which a Fire OG is placed on the Grape Ape tray, or vice versa.

Making clones for growers involves more than just technical precision, impeccable quality control and rare genetics, Grace says. Dark Heart works in collaboration with breeders and growers to create strains that prove popular in the market place and rewarding in the grow room.

Instead of chasing after the trendiest strains that become fads and then fade away, Grace and his collaborators do rigorous genetic testing, plant growth monitoring and evaluation of harvest weight and percentages and ratios of cannabinoids and terpenoids. They also create strains targeted toward subsets of growers, such as short-season Indica and Kush for indoor growers and long-season, ultra-hardy strains for outdoor growers.

Rare Phenotypes & Heritage Strains

Dark Heart offers rare phenotypes of perennially popular strains such as SFV OG, Blue Dream, and the famous Ken Estes Granddaddy Purple. They also offer you strains not found anywhere else. This includes Sour Diesel x Lemon Kush, a 50-50 Sativa-Indica cross that delivers weighty harvests of dense, resinous buds.

Of particular note are Midnight Splendor, a cross between a stellar Girl Scout Cookie phenotype crossed with native Hawaiian genetics that produces massive yields, and Napali Pink. Both are bred on the Hawaiian island of Kauai.

Dark Heart’s high-CBD Chocolate Tonic and Guava Jelly strains are high-yielding and easy to grow. Another tasty strain is Strawberry Banana, renowned for its copious resination that produces a bounty of cannabis concentrates and its banana and strawberry terpenoids scent. Dark Heart also features many strains from the Emerald Triangle’s lauded Humboldt Seed Company, including Venom OG, Blueberry Muffin, Strawberry Cheesecake, and quick-maturing Pineapple Upside Down Cake.

“Dark Heart Nursery is a uniquely valuable partner for those of us breeding and perfecting rare cannabis strains for the pleasure and profit of thousands of legal California growers,” says Humboldt Seed Company’s Nat Pennington. “They’re partners in our regional phenotype hunt, and we’re blown away by the consistency and professionalism of their operation. When people go to dispensaries looking for the best strains and healthiest clones, they ask for Dark Heart.”

This photo below shows Grace and some of the Dark Heart crew with team members from professional breeders Humboldt Seed Company and Humboldt Indoors, at the Humboldt Indoors facility. These good people love cannabis just like you do. Talk to your local dispensary about getting their strains and clones right away!