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planting cannabis seeds in rockwool

Rockwool Growing Cannabis Seed Strains

Rockwool growing cannabis seed strains is easy, clean and productive. Professional growers of flowers, veggies and all types of plants like rockwool because it is very clean, light weight, sterile and allows for the management of air to water ratios at the roots to maximize results. Rockwool is also great because you only need a very small amount to grow a lot of bud versus soil. It’s not hard to yield a half pound plant in only a six inch pot or cube of rockwool. When the crop is done there is only a small and light weight amount of media that has to be disposed of or repurposed–way easier than lugging giant bags or bales of moist dirt around.

What is Rockwool?

Rockwool is a fibrous. porous and inert material usually made from spinning molten basalt rock like cotton candy and letting it cool. It is then cut into cubes, slabs or granules and wrapped in plastic sleeves. Rockwool is relatively inexpensive and fairly widely available.There is also a material used for growing crops called “glass wool”. It is less common but it shares similar properties to rockwool. Note to only to use horticultural grade rockwool–industrial grades may be used as fire retardant insulation. They are not the same, although they may look similar!

Why Rockwool for Growing Cannabis?

There are several good reasons why rockwool is popular with professional growers—home growers may also share and reap similar benefits, including:

Rockwool growing cannabis seed strains can yield heavy crops without a whole lot of growing medium. Because hydroponic growing nutrients supply all of the necessary elements hungry buds need to swell to maximum potential, the growing medium volume doesn’t need to be nearly as big as with soil.

Rockwool growing cannabis seed strains gives growers lots of control over the root environment, making it easier to keep roots happy and more productive with more air around the roots. Rockwool is very porous and water moves very well through it–roots don’t need to be kept soaking wet; it makes them grow healthier and take in more nutrients. Using flood and drain or drip trays with a reservoir, pump and a timer gives easy control over air to water ratios 24/7.

Since automation is easy with rockwool gardens, growers can spend more time tending the crop doing important things like pruning, checking for issues and managing the growing environment–all the many little jobs that add up to healthier crops of buds that yield heavier!

Rockwool growing cannabis seed strains is very neat and tidy. Horticultural grade rockwool is totally sterile–guaranteed not bring any problems into the garden like root disease causing organisms or insect eggs and nematodes. The same cannot be said of most garden soils.

How To, Rockwool Growing Cannabis Seed Strains Basics

For cannabis seedlings, use starter plugs or two inch rockwool cubes.

For young vegetative cannabis seedlings, ie two to four weeks, use three to four inch rockwool cubes or loose rockwool flock in pots.

For final transplant before flowering and budding, use six inch rockwool cubes or one gallon pots with rockwool flock or three to four inch cubes on top of rockwool slabs.

Pre-treat rockwool before growing your cannabis seed strains. This is to help condition it for proper pH levels before use because rockwool is very alkaline (high pH). It’s easy to do–just soak for 24 hours or as directed by label in a mild fertilizer solution with a pH of 5.5. Liquid pH test kits or test strips are inexpensive, easy to get and accurate enough. Digital testers are also available.

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Once planted, DO NOT OVER WATER ROCKWOOL! Rockwool is very porous, you want more air around roots—keeping it soaking wet does not help, it hurts. Let rockwool dry out to half of the wet weight (get a feel for it, pick it up) before lightly irrigating again. Rockwool is somewhat forgiving, thankfully. However, a long stretch of staying fully saturated can create problems in some root sensitive strains.

For feeding crops of buds growing in rockwool only use mineral hydroponic nutrtients. Organics will clog up the pore spaces and create all kinds of problems. Following a hydroponic feed chart using hydroponic fertilizers in each growth phase makes it easy for anyone to get heavy yielding and high quality crops without a lot of hassles or mess. Just stick to the formula and keep a healthy environment and reap the rewards!

Starting Cannabis Seeds

This is one of the easiest germination methods and doesn’t leave a lot of room for error. Cannabis seeds and clones can be expensive, and sometimes we have genetics we just can’t afford to lose. When that’s the case, germinate your cannabis with one of the following recommended option to ensure as close to 100% germination rate as possible.

Rapid Rooters (Highly Recommended For All Setups)
Rapid Rooters are easy to work with – you just stick your cannabis seed in the Rapid Rooter (pointy side down), keep your seed warm and slightly moist, and let the Rapid Rooter do its magic.
Sprouts emerge and roots appear in just a 4-14 days.
Rapid Rooter starter cubes are suitable for all growing methods, including hydroponics, coco coir and soil. They work for every setup and come from General Hydroponics, a trusted company (the same one used by NASA) which is known for the quality and consistency of its products.
I highly recommend using Rapid Rooters over any other starter plugs. They are less prone to problems and work great with any growing medium (including hydroponic systems).

Pros of Rapid Rooters
Easy to Use – You Can’t Really Mess Up
No Prep or Setup – Open the Package and Go
Some of the Best Germination Rates of Any Method

Cons of Rapid Rooters
Can only get 50+ at a time (General Hydroponics currently does not offer fewer plugs per package)
After opening the package, you only have a week or two before they dry out, so if you’re only germinating one or two seeds, you’ll end up having to throw many of the Rapid Rooters away.

These are Round on bottom (won’t stand up by themselves without support) unless you squish or trim the bottom so it’s flat & will stand on its own until placing directly in final destination (hydro, soil, coco coir, etc). These are the best choice for a hydroponic setup where the Rapid Rooter will be placed directly in the final destination. In our hydroponic setups, we’ve had almost 100% germination rates with Rapid Rooters, better than any other seedling cube we’ve tried.

Perfect for cloning or starting seeds with a humidity dome (standard 10-inch by 20-inch dome like this one – 7-inch height recommended for cannabis seeds or clones)
Easy to transplant to new destination
Just add water and seeds, that’s it!

Rockwool Cubes (Not Recommended)
It’s often hydroponic cannabis growers who use Rockwool cubes since these can be safely placed in hydroponic setups, hold a lot of moisture, and are resistant to mold. Rockwool is cheap and easy to find. It comes in convenient cubes. But it does have some major drawbacks…

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Pros of Rockwool
Cheap & Easy to Find
Inert Medium (useful for hydroponic growers)
Cons of Rockwool
Bad for the environment (unnatural material that does not break down)
Bad for your health (especially your lungs) – wear gloves and cover your mouth/eyes when handling Rockwool
Has a pH that is too high for cannabis, so it must be thoroughly rinsed and treated
Poor cloning and germination rates
Difficult for new growers

Rockwool cubes are bad for the environment
Rockwool is not a natural material – it’s made by heating rock and chalk to 3,000°F and air is blown through the mixture to create thin fibers of rocky material
It does not break down naturally and therefore after Rockwool is created, it will remain in that form basically forever, filling up landfills without breaking down for thousands of years.
Rockwool cubes can be bad for your health
Rockwool is dusty and needs to be rinsed thoroughly before use. Little pieces of Rockwool and dust can easily get in your eyes, skin and mouth. Small strands or fibers can get lodged in your lungs if you breathe in Rockwool dust, and it’s unknown if these fibers can ever get out again.
Protect yourself! Always use a mask, goggles and gloves when working with Rockwool.
Rockwool cubes have a high pH until they’re treated
New Rockwool cubes have a high pH – too high for healthy cannabis seed germination. Therefore it’s important to thoroughly rinse Rockwool cubes in pHed water, then let them soak in pHed water overnight before use. Since Rockwool holds onto a lot of water, after soaking they should be given a few days to dry out before planting seeds or making clones.
Rockwool cubes do not get great germination rates
Rockwool can be difficult to germinate marijuana seeds in, so I recommend most beginner growers sprout their seeds using another method like Rapid Rooters (mentioned above) which can also be used in hydroponic applications but are less prone to germination problems.
Many growers have placed seeds in Rockwool cubes, only to wait for weeks and never see seedlings appear.
Some growers seem to have no problems, yet many other growers suffer through very poor germination rates. Some seed companies will not honor seed germination guarantees if the grower uses Rockwool because it is notoriously bad for germination.
If you do use Rockwool, it’s recommended you germinate your seeds using another method like the paper towel method, then transplant your seeds to the Rockwool cubes after roots have already appeared.
Even when following all the best practices, we just have not gotten great germination rates with Rockwool cubes, and it’s common for new seedlings not to make it.
We also had trouble rooting clones in Rockwool. Rockwool cubes just don’t hold enough air to get plenty of oxygen to the roots, and they tend to hold onto a lot of water and get waterlogged easily. Since Rockwool can hold a lot of water, it’s prone to “drowning” seeds
I highly recommend using Rapid Rooters instead for your hydroponic application (or any grow setup), as they are much more user-friendly and tend to get far better germination rates.

What is Rockwool and Why Is It a New Buzzword in the Marijuana Industry?

Rockwool cubes could be the future of hydroponic growing

Rockwool for Hydroponic Marijuana Growing

Rockwool is a fantastic method for growing marijuana!!

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With Rockwool, you can have the strain you choose through the cannabis cycle as growers of all levels utilize different hydroponics for harvesting heavier yields. If you haven't tried Rockwool, it is time to hop on the trend.

Rockwool uses the power of natural stone to produce an aerated and fluffy growing means for cannabis. It is a material that drains well and supports the development of the plant's roots. This article will provide insight into why you should use Rockwool in hydroponics and soil systems and how it works at every stage of the growing cycle.

What is Rockwool?

Rockwool is a form of mineral wool, a material used as acoustic insulation in constructing hospitals, stadiums, and homes. The product was created by Danish founders who aimed to develop stone wool in Germany, Scandinavia, and New Jersey. For over a century, the company has made an effective product.

Aside from being an important building material, Rockwool also aids the growth of millions of cannabis plants. The substance in Rockwool brings many benefits to the cannabis grower: it doesn't contain organic material making it immune to decomposition from fungi and molds.

Rockwool doesn't contain heavy metals; these are metals that contain chromium and lead, which are toxic to plants. These heavy metals also make the plant have yellow leaves because it prevents photosynthesis and kills the plants.

Why Rockwool is utilized to grow cannabis

Rockwool provides numerous benefits for a cannabis grower. Aside from the fact that it prevents the multiplication of pathogens, it also helps the seeds germinate, thus facilitating good drainage.

Its cubes are sterile and inorganic which means it arrives at the grower's place clean and ready to use. It also doesn't protect the root of your plants against damage from microbes. Although Rockwool takes a longer time to break down, growers can shred used blocks to matter and throw them into the compost pile finely. Over time, the basalt rock in Rockwool will leach into the compost, providing an added nutritional benefit to your soil. Hydroponic cannabis growing is called "dro weed".

The Rockwool cubes get saturated with water when you soak them, and it drains away quickly. Every cube has small spaces between the fibers, which effectively drains water. But don't overwater the cubes because excess water may suffocate the roots and negatively affect plant growth.

Rockwool cubes offer a haven for your cannabis seeds during germination. When you keep the plants sufficiently saturated, they will give you the critical things needed for productive germination. These key things include moisture, warmth, and darkness.

With Rockwool, it is easier to transplant your cannabis seedlings when they are ready or in a new home. You wouldn't have to struggle with moving the seedling directly into the pot full of soil or in a hydroponic net pot. Unlike other transplanting processes, you wouldn't need to break the initial growing medium, thus minimizing any mess.

How can you use Rockwool to improve your cannabis?

So now that you know a lot about Rockwool cubes, including their benefits, how can you use them? Before putting the seeds into the cubes, you should adjust the cubes' pH to have less alkaline. This move will allow you to infuse nutrients into the cubes, thus giving your seedlings a better start at life.