I constantly am asked, "what do I NEED to grow nice plants?" People are always trying to scrimp and save and get the maximum growth despite. I understand this ... good lighting, pressurized CO2, good test kits, etc. are all expensive, and really start to add up as you advance towards a more high-tech aquarium.

First things first, I think that the bare minimum can be achieved without investing in all the bells and whistles that us high-techers use. In other words, you CAN grow plants without CO2, you CAN grow plants without lots of good-quality lighting, you CAN grow plants without supplemental fertilization, and you CAN grow plants in nutrient-poor substrate. You can do all of these things, but like anything in life, there are trade-offs.

First, I suggest you look at your overall goals. Is your goal to spice up an aquarium with a plant here and there? Is your goal to provide plants to act as "nutrient sponges" so you don't have to do as many water changes? Is your goal an award-winning aquascape? After you have determined your overall goals, you can proceed with discerning what you need from what is not necessary.

As I said, there are trade-offs. There are plenty of low-light species of plants, there are many plants that will do well w/out supplemental CO2. However, there are also many plants that will not do well in those conditions. If you try, the plants will fail. If you want to have a broad pallet of plants with which to paint your aquascape with, you will need to add things like good light, CO2, good substrate.

I will use an analogy here: plants are like engines.

A car engine needs basic things to run ... it needs gas to fuel it, oxygen to allow combustion, oil to lubricate it, coolant to keep it from locking up, electricity to power the spark plugs, a place for exhaust and waste to go. If you take away or change any one of these factors, the engine will either no longer run or no longer run well.

Plants are very similar. They have things that they simply need to grow. A plant needs light, CO2, and nutrients to photosynthesize. If you reduce any one of these components to below-optimal levels, the plant will slow down or stop photosynthesizing all together. It would be like running your car with the carbs way too closed. The engine might run, but without sufficient oxygen to generate combustion, it will sputter and probably die.

If you try to grow your plants with everything optimal, but a single component is not, then your plants will suffer. An engine cannot run unless it gets what it needs ... plants are no different.

So where am I going with this? As folks wonder, "maybe I don’t need CO2 to grow this." or "I think 1 watt per gallon of light is sufficient for me", they may or may not be correct. If the goal is to grow some java moss for a spawning site, then yes, no CO2 or good lighting is needed. However, if the goal is to grow a thick mass of stem plants, then most likely they will fail.

My next point is that, once we get lighting and substrate in order, we are no longer trying to grow plants. Growth is the byproduct. We are trying to prepare the water. To explain: supplemental CO2, macronutrients, micro nutrients, water hardness ... all of these items are critical to a plant's growth. However, none of these things is dosed to the plant -- they're all dosed to the water. This may seem obvious, but so many people miss the forest for the trees. If we provide the right water conditions, enough light, and a good substrate, then plants will grow! The challenge lies in properly preparing the water.

That brings up the next question: "So you're saying I need EVERYTHING. What do I do first?" Well, you don't need everything, unless your goal is to have the most possible plants available to you. But, if that is your goal, you must understand that you cannot add a single component and gain the growth of a complete system overhaul.

Case in point: back to the car engine analogy. If you want your car to run faster, one of the first things you do is expand the exhaust pipe. That allows the engine to ventilate faster, leading to more combustion, generating more power. Lets say that you don't want to mess with the exhaust system, but rather adjust the carbs so that you are putting more fuel and air into the motor. What you'll get is a disaster. To an extent, plants are the same way.

If you want to ramp up your growth, and add fertilizers, you'll be in a world of hurt. Why? Well, the plants are only going to grow as fast as their most limiting factor. IOW, if you add a 400-watt MH light and dry-dose the heck out of your tank, but don't adjust your CO2 accordingly, the plants will not benefit. If you blast your tank with light, saturate the water with CO2, and don't dose nutrients accordingly, your plants will not benefit. About the only thing that you can add freely, at nearly any light or nutrient level, is more CO2 (but don’t kill your livestock -- that's a whole 'nother post). CO2 is like the oxygen component of combustion ... if you add more it can make what gas you have more flammable. If you don't have enough, nothing will burn.

So, if you are low-tech and you're looking to make the high-tech plunge, the first thing I would recommend is trash your DIY CO2 and go pressurized. After that, increase your light, and those two things combined will necessitate nutrient dosing.

Regards,
Reggie Bustinza