how many plants for 40g

[kvokal]

I got a tank that is 36 x 16 x 18(D). How many plants would I need if I want to have a planted tank? Thank you.

[lefty o]

1 or more. it comes down to how many do you want, what do you like. thats all there is to it.

[FrozenFins]

yes @lefty o said a planted tank is a tank with plants in it. I consider planted tanks to have the centerpeice aquascape be a plant. All though you could have one Amazon Sword and it still be a planted tank

[JettsPapa]

Somewhere between 1 and 100.

[kvokal]

Ok, if I say "sustainable" planted tank, would that help? 1 or 2 plants will not make it sustainable. Of course carpet of plants will take 100+ or so. I wondered as large plants or the ones I would need to start to make it sustainable. Thanks.

[H.K.Luterman]

I guess it depends on what kind of plants you're interested in.

If you want the plants to serve mainly as filters, you would need to buy very fast growing things: I would recommend hornwort. Stem plants like water sprite, anacharis, and water wisteria are also fast growers that take up tons of nutrients. Also there's a ton of variety of stem plants, and mixing and matching them can produce some nice effects. 

[JettsPapa]

11 hours ago, H.K.Luterman said:

I guess it depends on what kind of plants you're interested in.

If you want the plants to serve mainly as filters, you would need to buy very fast growing things: I would recommend hornwort. Stem plants like water sprite, anacharis, and water wisteria are also fast growers that take up tons of nutrients. Also there's a ton of variety of stem plants, and mixing and matching them can produce some nice effects. 

Floating plants would also help.  Other than the plant selection, I assume stocking levels would affect that number also.

[Struggle]

I’d do one per 2 gallons so (20) plants to start with.

[kvokal]

Excellent, these last post help a lot. I might order them to day since I got the rest of things ready. Thanks much.

[Brandy]

This thread shows how plants filled in in my 29g over time. I sterted with 10 valisnaria and some water lettuce. You can see I added many more. Some made it, some didn't. Your level of patience is a big part of this, you can see how big your footprint is, and how big you expect plants to get... I would suggest floaters to jump start tanks. I have just started a new 40g and have again started with Valisnaria and water lettuce...

 

[kvokal]

That's excellent! What state do you live in? I live in CO and it seems nothing grows well here at all except the aspen trees and needle trees! 😁

[Fish Folk]

Still not 100% sure what you mean by "sustainable." If you fertilize / (or keep tons of fish) and use root tabs + use a quality light for the depth of the tank, you'll be able to add a ton of plants _eventually_. What you need is to achieve balance as you go, step by step.

You can usually add a dozen plants without much drama, but it's important to know what they need and how they'll grow for you. In a 40 gal breeder, stem plants will need light to reach through to sustain the bottom leaves. If they're not happy, they'll die off at the bottom and just put growth up to the top. Swords need root tabs. Valisneria likes root tabs. Some plants grow alright floating as long as there's enough nutrients in the water column. But if they block out light across the top, of course, that impacts lower plants.

The tank will need to settle out its parameters before you'll be able to avoid algae blooms, nutrient crashing, etc. If you've never kept a planted tank before, start out with some hearty plants that are hard to kill. Java Fern is pretty tough. Wisteria (hygro) loves our soft water. Greg Sage (Select Aquatics) does really well with Bolbitis. You may consider testing the Carbonate Hardness / General Hardness / TDS of your water. That may not provide comprehensive mineral-spectrum feedback, but if you learn that your water is either very soft or very hard, it can help you dial in on what fertilizers to use. Are you planning on keeping fish in the tank? 

Best book we've enjoyed from our local library (I'm sure you can order it through Interlibrary Loan in CO) is "Sunken Gardens" by Karen Randall (see book cover photo below). [[Oh please, please Randy . . . she needs to be interviewed on the Aquarist Podcast!!]]

Of course Aquarium Co-Op is awesome. Cory has forgotten more about plants than most of us will ever learn. 

Check out Bently Pascoe YouTube channel. He's a plant lover! 

Irene (Girl Talks Fish) gave a _really nice talk_ on keeping planted tanks at our Fish Club (PVAS) Zoom meeting the other week. It was great! She's an excellent teacher / communicator. 

Good luck!!