Plant Basics?

ParadoxLiz

ParadoxLiz

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Oct 27, 2005
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www.lizmcguireonline.com
All,

I've been doing a lot of research on how to keep plants and am hoping someone would be kind enough to confirm or correct my conclusions and answer some questions.

1. I understand that different plants need varying amounts of light and some need a substrate while others will attach to rocks or driftwood; also, different plants grow to different sizes. This should all be researched and the proper plants/conditions chosen/arranged. Makes sense.

Can anyone give a general listing of how many watts per gallon equate to low, medium and high lighting?

There seems to be some difference in the light requirements with very small tanks (those under 10g?) - is it that they need more watts per gallon (because the wattage is so low) or that they don't need as many watts because they're more shallow, or....?

2. Plants need carbon - this can come from CO2 (either what's in the water or from an injection system) or from a liquid like Flourish Excel. There are tests to measure CO2 in water, these or the instructions on the bottle (plus observation) can be used to determine amounts needed.

3. Plants need nutrients. From what I've read, it's possible they'll get enough ammonia, nitrite, nitrate from the fish (but testing is needed and if the nitrate is too low, it may be necessary to add nitrate).

Phosphate may come from your water; depending on how much your water has, you may need to add some. There are test kits for this.

Potassium - this probably needs to be added. There are some tests, but they seem rare and pretty expensive. Probably best to follow the directions for the fertilizer and/or use "nutrient deficiency" symptoms to determine if this is needed.

"Trace nutrients" - it seems like the amount needed is based on the results of iron tests or that you simply add based on the recommendations on the bottle. (Is it safe to assume that calcium, magnesium and sulfate tests aren't needed (for the average person)?).

Which of these (trace, nitrate, phosphate, potassium) can come from the substrate (at least for plants planted in the substrate)? Do any of these nutrients leach into the water for plants not planted in the substrate?


Assuming the plants, lighting, carbon (dioxide), substrate and fertilizers are all properly selected / applied, one should have a healthy planted tank, no?

Thanks,

Liz
 
'Can anyone give a general listing of how many watts per gallon equate to low, medium and high lighting?'

In tanks over 20 gals. or so, 1.5 wpg = low; 2.0 - 3.0 or so = medium; over 3.5wpg or so = high. This is very subjective and answers will vary.

Comparing one's kH and pH on available charts or calculators is the best way of determining CO2 concentrations in the water table.
There are many test kits available for testing other nutrients, but many of them are hard to read and in some cases unreliable. The ones that will give you a reasonable amount of accuracy are for P, N, pH, kH. The rest are a waste of money and in most cases, unnecessary when doing a weekly water change.

At low or even moderate light levels plants, in many cases can do quite well on available nutrients especially in conjunction with a nice fish load, because less light allows slower growth and requires less need for supplemental nutrients.

If you are supplementing macro nutrients it is a good idea to add a trace mix to your list as well for balance. All dosing revolves around balance with plant load and wattage.

'Which of these (trace, nitrate, phosphate, potassium) can come from the substrate (at least for plants planted in the substrate)? Do any of these nutrients leach into the water for plants not planted in the substrate?'

There are traces of all of them in the substrate, but most nutrient dosing releases them into the water table where most stay until used or dissipate over time.

'Assuming the plants, lighting, carbon (dioxide), substrate and fertilizers are all properly selected / applied, one should have a healthy planted tank, no?'

Just change selected/applied to balanced and you have the idea, IMO.

Hope this answers some of your questions. :)

Regards to Chomp!!

Len
 
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ParadoxLiz said:
Can anyone give a general listing of how many watts per gallon equate to low, medium and high lighting?
Click to expand...

Low: 1-2WPG
Medium: 2-3WPG
High: >3 WPG

ParadoxLiz said:
There seems to be some difference in the light requirements with very small tanks (those under 10g?) - is it that they need more watts per gallon (because the wattage is so low) or that they don't need as many watts because they're more shallow, or....?
Click to expand...

Yeah I would like some clarification on this point too.


ParadoxLiz said:
2. Plants need carbon - this can come from CO2 (either what's in the water or from an injection system) or from a liquid like Flourish Excel. There are tests to measure CO2 in water, these or the instructions on the bottle (plus observation) can be used to determine amounts needed.
Click to expand...

Correct...Measure Your KH and PH to determine C02 levels. Generally advised to suppliment Carbon for anything over 3WPG although its beneficial to do it in most set-ups.

ParadoxLiz said:
3. Plants need nutrients. From what I've read, it's possible they'll get enough ammonia, nitrite, nitrate from the fish (but testing is needed and if the nitrate is too low, it may be necessary to add nitrate).
Click to expand...

Dont think they utilize Nitrite...and the amount of Nitrate generated from the fish could be sufficient, but that depends on your Phosphate levels. My Phosphate levels are high comeing out of my tap...2ppm so I try to keep my Nitrates around 20ppm....10:1 ratio - For this I have to suppliment Nitrate otherwise it gets too low. An essential test for keeping a Balanced tank. PO4 and N03

ParadoxLiz said:
Phosphate may come from your water; depending on how much your water has, you may need to add some. There are test kits for this.
Click to expand...

Yes...and as I explained above that will determine your Nitrate levels as well.

ParadoxLiz said:
Potassium - this probably needs to be added. There are some tests, but they seem rare and pretty expensive. Probably best to follow the directions for the fertilizer and/or use "nutrient deficiency" symptoms to determine if this is needed.
Click to expand...

Yeah, thats what I do...definatley add some after my weekly water changes and dose another later in the week. From what I understand its pretty hard to overdose this stuff.

ParadoxLiz said:
"Trace nutrients" - it seems like the amount needed is based on the results of iron tests or that you simply add based on the recommendations on the bottle. (Is it safe to assume that calcium, magnesium and sulfate tests aren't needed (for the average person)?).
Click to expand...

I would say yes.....usually treated tap water is on the hard side and contains sufficient amounts of those elements, but there are obvioulsy a ton of different variables and amounts....good to get a report from your local water dept.

ParadoxLiz said:
Which of these (trace, nitrate, phosphate, potassium) can come from the substrate (at least for plants planted in the substrate)? Do any of these nutrients leach into the water for plants not planted in the substrate?
Click to expand...

I would say that entiley depends on the substrate and the plant, and ill leave a more detailed response for someone more knowledgeable to answer. I would assume a Sword plant which is a heavy root feeder will try to get Nitrate from the substrate if it is available as well as Phosphate. Any other element I would think you would need a plant specialized substrate to suppliment...stuff like Potassium and Iron will not be readily available with normal gravel.


ParadoxLiz said:
Assuming the plants, lighting, carbon (dioxide), substrate and fertilizers are all properly selected / applied, one should have a healthy planted tank, no?
Click to expand...

Yeah but easier said then done. I will say my biggest mistake was not balancing the Nitrate and Phospahte levels.......so make sure to do that
 
Sounds like you have a good handle on everything so far. It's not an exact science, don't worry! Especially if you don't have a ton of light.

For a 10 gallon tank, I'd say djlen's general wpg guideline would be about right. But for a much larger tank, say 70+ gallons, I think the cutoffs drop a little bit. Around 3+ wpg would be pretty high I'd say. Again these are just general and really don't dictate how your tank should be run.

You've probably figured this out already, but the higher the light the higher nutrient demands from the plants (including CO2) will be.

Some substrates have nutrients in them straight from the bag. Others, like sand and gravel, are called inert and have nothing available to the plants. Don't rely on many nutrients from the substrates no matter which one you have, unless you are adding root fertilizers or something like that.

Plants can take nutrients in from the water column and from their roots. I believe they first look to the water column and find it easier to get them from there but that may not be correct.
 
The scale I use:

Low light: 1-1.5wpg
medium low light: 1.5-2
medium: 2-3
medium high: 3-3.5
high: 3.5+

The wpg rule applies to tanks within the 20g-100g size. The rule doesn't apply to smaller tanks because the amount of energy released by the smaller light bulbs are just not enough to benefit plants much. Conversely, a very large tank doesn't need to follow the rule because the light bulbs used are much more intense with better depth penetration.

The wpg rule isn't a hard set rule, especially with the more efficient lights we have (PC, T5, MH). The rule is there to keep things simple, you meet the basic lighting requirement and lighting won't be the problem.

Plants need carbon for the photosynthesis process. Carbon dioxide can be measured by comparing your pH level with your kH level, provided there are no additional buffers present.

Plants need a variety of nutrients divded into macro and micro nutrients. Macro nutrients are nitrogen (ammonia and nitrates), potassium, and phosphorus. Micro nutrients are trace elements consisting of many minerals like iron, magnesium, calcium, etc. Tap water contains many of these nutrients in small amounts but you may need to add them depending on how fast your plants grow.

Plant substrates usually contain a high amount of iron and trace elements, the leeching that occurs is minimal as much of it is baked into the substrate material. Some plants are heavy root feeders and some are not, even though they are planted. Amazon swrods are heavy root feeders while anacharis is primarily a water feeder.

If the light requirements of the plants are met, and there is available CO2 and nutrients, then the plants should grow.

Given enough lights with
 
knashash said:
My Phosphate levels are high comeing out of my tap...2ppm so I try to keep my Nitrates around 20ppm....10:1 ratio - For this I have to suppliment Nitrate otherwise it gets too low. An essential test for keeping a Balanced tank. PO4 and N03
Click to expand...

Thank you for all of your answers and esp. for this - it's new to me. The water company puts their water report online, so I'm able to use that easily. I'm planning to get a Phosphate test (at least to get an idea while I'm starting out).

Thanks so much for your reply!

Liz
 
djlen said:
'Assuming the plants, lighting, carbon (dioxide), substrate and fertilizers are all properly selected / applied, one should have a healthy planted tank, no?'

Just change selected/applied to balanced and you have the idea, IMO.

Regards to Chomp!!
Click to expand...
Thanks, Len! Very good info and I'll keep the word "balanced" in mind.

Chomp says "woof!" :-)

Liz
 
Captain Hook said:
Some substrates have nutrients in them straight from the bag. Others, like sand and gravel, are called inert and have nothing available to the plants. Don't rely on many nutrients from the substrates no matter which one you have, unless you are adding root fertilizers or something like that.
Click to expand...
Thanks for covering this one - I've got Flourite in a new tank and was wondering how much help it would be with nutrients. Seems like (from what I can find) it's good for trace nutrients for plants that need the substrate, but wasn't sure...

Appreciate your response,

Liz
 
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