Author Archive for David Robinson

Nutrients & Additives

Nutrients & Additives: The #4 Factor In Maximum Yield

nutrients-3It can be very helpful to utilize the triangle of photosynthesis to understand lights on metabolism. Light energy in the presence of CO2 and water and nutrient is processed into sugars and starches. This is lights on metabolism. If you don’t have enough CO2 in your garden, the light that you are paying to generate will literally bounce off the leaves. If we don’t have enough water and nutrient to support the process of photosynthesis, the plants cannot process Co2. Whenever we are assessing situations in the garden we have to keep the triangle of photosynthesis in mind.

Upon first inspection, this topic is going to appear overwhelming. There are so many different nutrient companies offering different nutrient lines. But, 4l-massivejust as when you walk into the supermarket and there’s five different brands of bread, keep in mind that a lot of these products are different brands of the same thing. So what I want to communicate to you is the principles of the matter. You need what we call “a main food” or a “basefood”. The main food is going to comprise all of the necessary macro and micro nutrients. Main foods, whatever the form, are all going to be mostly complete. It can even be as simple as a one part organic product that you use from start to finish with no additives to produce clean medicine. The number one nutrient requirement you need to address is the main food.

In addition to the main food many gardeners routinely use some supplements. Standard supplements include B-vitamin formulas which are known to reduce stress, calcium/magnesium additives (typically not enough of these important nutrients can be included in a main food), root stimulators and bloom enhancers. There are a few other products that you might chose to use like microorganisms which can colonize your root zone, stimulate root growth and facilitate nutrient uptake. Organic gardeners may also consider the use of humic and fulvic acids needed to break down organic sources of NPK into the chemicals available for nutrient uptake.

nutrientdenseLet us take an in depth look at the flowering process. Other than our main food, calcium and magnesium is one of the most important flowering additives that we can consider. Calcium and magnesium assist in the hardening of fruit and flowers and calcium facilitates nitrogen uptake. From there, we have the additives that actually blow up flower size. These additives typically increase the amount of P and K that is in the nutrient solution and provide some additional natural stimulants to the flowering process. Flowering additives usually do increase yields substantially.

One of the other supplements that you may benefit from in the flowering process is a carbohydrate additive in a liquid or powder form. These additives give the plants energy without making them work for it. Other considerations may be root disease controls and an additive which is going to increase the essential oil production of your particular plant.

nutrients-1Those are your needs. Talk to your local hydroponic retail professional and find out how you can gain access to these yield enhancing products. It’s hard to remember everything all at once. So keep in mind that good nutrient manufacturers put together what we call feed charts, with weekly schedules to help you focus on exactly how to mix your nutrient solution so that you get the best use of the products you’ve purchased. Once you get into this process you are going to find it’s like following a recipe and you will probably really enjoy feeding your plants and mixing nutrient solutions. Just remember to keep an eye on your parts per million and your PH so that your plants can really make use of these excellent nutrient solutions that you’re going to apply.

Systems & Set Up

Systems & Set Up: The #3 Factor In Maximum Yield


systemsMany gardeners think that there is one particular system that is going to lead them down the path to success. I always say to people: I’ve seen great yields out of every system there is and I’ve seen poor yields out of every system there is. What it really comes down to is; understanding how plants grow and applying that knowledge to your system. You need to know the ins and outs of the particular system that you choose.

systems-mediumsFor example drain to waste gardens are very common and allow great flexibility in medium and nutrient choice and plant size. A major advantage of the drain to waste system is that fresh nutrient solution is applied every irrigation and we can catch the runoff and track the ppm and ph.

This article is only an overview of systems that can be chosen, in order to properly run any chosen system we must take the time to investigate the potential pitfalls. For example in recirculation systems flood and drain gardens can be low risk and low labour. You can definitely load a lot of plants into a table with 4 inch Rockwool cubes on slabs. NFT systems – nutrient film technique, where a thin film of nutrient passes over the roots can also be low risk and low labour. Aeroponic gardens deliver a fine mist of nutrient solution to the roots. Top feed drip systems can systems-3 be utilized with many different mediums and container sizes. If we are moving to larger plants like trees, we might consider a system that allows us to space the plants accordingly. In the case of growing larger plants an appropriate vegetative system must also be considered to obtain efficient flow between vegetative and flowering stages of growth. Deep water culture systems offer good flexibility for different plant sizes.


The word “hydroponics” means to work with water; ultimately we are limited by our understanding and imagination. Having said this do not feel like you need to reinvent the wheel. Often a good way to proceed is to follow the system of a gardener who consistently obtains bountiful yields of the same strain you are growing.

coolcolor2As long as you chose a system that supports the genetics you’ve chosen, then you can build the rest of your environment around the system and you will be well on your way to getting good yields. Again I can’t emphasize enough developing the knowledge that you will need to work the ins and outs of the particular system that you chose. So once you have focused your attention on the genetics that you need, identified where you can get them and what their important characteristics are, you can move forward on selecting a system, talk to your local hydroponic retail professional to receive guidance in using that particular system, or consult the Grower’s Handbook, Teachings of the Garden Sage, which tells you all the ins and outs of each particular system.



Environment: The #2 Factor In Maximum Yield

Once we have obtained genetics that are pest and disease resistant and yield the desirable characteristics in good quantity we can turn our attention to “conforming the garden to our plant”.

Environmental basics can be considered in terms of what works 90% of the time. Obviously there will be exceptions to these rules as we look at fine tuning an environment for a specific strain.

Our indoor environment starts with lighting. Current debates are between the proven HID lighting and LED lighting. LED lighting has great future potential, but at this time, in my experience it does not produce the largest yields per watt. LED lighting appears attractive due to the perceived power savings, however, we calculate yield per watt. So it does not matter if you are running less power if the yield per watt is not adequate.

environment-love-consistencyWe used to be happy with 1 gram of dry plant material per watt of lighting. With the new double ended HID lighting technology my clients are not happy unless they are getting 1.4 grams per watt. Some clients even claim 1.8 grams per watt to be the new goal. These numbers blow all previous records out of the water. Accordingly, DE lighting is my current recommendation. Some DE lighting even comes with very intelligent controllers, going far beyond a basic timer board, into environmental control like sunrise/sunset options, high temp shut off and auto dim. There is some debate on lighting layout. Some layouts create a higher amount of light intensity which may reduce yield per watt but increase overall production, while layouts with lower intensity will generally increase yield per watt with a reduction in total production.

Whichever form of lighting we select we must arrange it accordingly in our garden. It is usually best to consult with a professional on the specifics for each particular space and application.

Now that we have selected our lighting we must control the heat load. Heat load is normally calculated in BTU (British thermal units). We have a number of choices for cooling our gardens including air conditioners, water cooled chillers and intake/exhaust systems. The cooling method selected should be accurately sized to handle to heat load produced year round.

environment-7Another essential component of the indoor environment is Co2. Simply put, if we are not enriching with cold gas or burning gas to produce optimum levels of Co2 then we MUST move lots of air in/out of the garden.

Air movement within the garden is usually achieved with oscillating fans, potentially one per light. Essentially all the plants must dance in a gentle rhythmic manner.

Lights off temperature must be maintained with heaters on heating thermostats in cooler climates and in warmer climates with a cooling thermostat set to the lights off set point.

Basic environmental parameters are 80-85 degrees F during lights on. Lights off is maintained at 70 degrees F creating a 10-15 degree differential between lights on and lights off. A humidity of 50-60% is typical, although any of these parameters can be fine tuned for a specific strain. We can develop a vapor pressure deficit chart for our selected genetics.

environment6There are also certain circumstances that may require us to manipulate the environment for a specific reason, such as: to control vertical stretch during the first two weeks of flower we may employ a positive differential by bringing our lights on temp down to 78-80 degrees F and lights off temp up to 73-75 degrees F, or to control a spider mite infestation we might drop our lights on temp to 78 degrees F and raise humidity to 65%.

Factors That Maximize Yield Video Series

Greetings everyone, my name is David Robinson and I’ m the Garden Sage, author of “the Grower’ s Handbook, Teachings of the Garden Sage”. I started in the hydroponic industry 20 years ago at a store called Pacific Northwest Garden Supply in Surrey, British Columbia. At that time it was really the Mecca of indoor gardening. I enjoyed success in guiding my clients to good yields; I thought I was a pro. When I started designing a course on indoor gardening I realized that I knew what worked but not ‘ why’ . As I went deep into understanding how plants actually work I had my light bulb moments in which I acquired what I call the ‘ working model of a healthy plant’ in my mind. It is this ‘ working model’ that I use to this day to diagnose the plant problems of my clients. In 2003 I opened Pacific Northwest Garden Supply in Nelson, British Columbia. I spent the next 7 years refining my course into “the Teachings of the Garden Sage” which I published in 2010. This book is my life’ s work. I always say “it is the book I needed my whole career, and I had to write it to get it.”

lookat-plantAfter 20 years of working with the gardeners in BC helping them achieve the best yields they can, I’ ve come to realize that there are factors that go into maximum yield, and their order of importance is:

Number 1: Genetics

Number 2: Environment

Number 3: System/Grower

Number 4: Nutrients and additives.

lgp_1670I find that most new gardeners conceive this order of importance in reverse. They usually come in looking for a magic solution in bottle believing that nutrients and additives are the number 1 factor going into maximum yield. The next thing they conceive is that there is a holy grail of a system that will help them achieve those bumper crops. And then of course they may start to look at their environment, but often overlooked is the original foundation, the whole reason why we’ re gardening: The genetics that we’ re working with.