Pesticides and other risks of adding pothos monstera etc to grow out of aquarium

[Dave G]

I’ve started to grow a pothos out of the aquarium, bought from my lfs. I would like to add a monstera or other ones not at my lfs.  Obviously plenty of greenhouses to go out and grab plants but what specific risks could I be introducing?  I am concerned about pesticides and other unknowns that could harm my tanks out of ignorance.   Thanks 

[Expectorating_Aubergine]

The most common pesticides used in the nursery trade a neonicotenoids. Basically kinds of synthetic nicotine (like what's in tobacco). The tend to have a residual time of anywhere from a week to a couple moths. It's heavily reliant on the rate use, what kind of neonic it was, how it was applied and the environmental conditions that they are exposed to. Generally speaking they tend to have a short residual time and break down pretty easily in most environments. My personal experience is that the amounts present haven't had any negative effects on any fish or inverts. I've had plants that I bought from a big box store, took cuttings off and put them right in the aquarium. If you want to play it extra safe, you can grow a plant out and them take cuttings from the new growth. You could also get cuttings off a friend or relatives house plant. I find that most people don't use pesticides on their house plants. I would stay away from monsteras unless you have a LOT of space. They get HUGE, FAST when they are in aquariums. 

[OceanTruth]

On 11/6/2022 at 2:43 PM, Expectorating_Aubergine said:

I would stay away from monsteras unless you have a LOT of space. They get HUGE, FAST when they are in aquariums. 

Dang, I must have mine in suboptimal conditions. I’ve had a Monstera plant for a couple of months now and besides a little bit of root growth it hasn’t done much of anything else.

[Expectorating_Aubergine]

Mine took off like a rocket for a while. I had to keep cutting it back. Really cool, but probably not the best for a small space....

[gardenman]

In the gardening world there are two major types of pesticides. Applied pesticides that are sprayed onto the plant and systemic insecticides that are added to the soil/water and absorbed into the plant. In either case if you give the plant a month or two and don't let the soil come into contact with your water, you should be okay. Some commercial greenhouses these days rely on other means to control insects. A common technique is to fill the greenhouse with CO2. Plants love CO2 but insects tend to have a hard time breathing it. By sealing a greenhouse and bringing the CO2 level up to 1%-2% (or higher) they can both enhance plant growth and destroy many/most insects. This is done mostly on the commercial level as workers in those greenhouses with elevated levels of CO2 need to wear oxygen tanks while the supplementation is ongoing. In some cases, they'll temporarily vent the heater from an adjoining greenhouse into the one they wish to treat and the CO and CO2 from the exhaust gases will serve to suffocate any insect issues at essentially no cost. Once the desired exposure time has been reached, they'll then vent the greenhouse before letting workers back in. Pesticides are expensive, so most growers only use them when necessary. In most cases a plant produced in a large commercial greenhouse should be relatively free of any pesticide that can harm your tank or fish.

[TOtrees]

The suggestion above from @Expectorating_Aubergine to grow it out, then put just a cutting in the tank is likely an easy and safe way to go. I would take a cutting, put it in water until some decent aquatic roots develop (takes a few weeks at least), and after say 4-8 weeks put the rooted cutting into whatever holder you have in your tank. I would definitely avoid getting any soil from the original purchased plant in the tank, since you would have no idea what that's been treated with, or when. 

Another good precaution would be carbon in the filter (or in a mesh bag in the tank if filter not possible). Not saying you need it here, but just reminding OP and others that carbon is great at breaking down organic compounds, and this includes pesticides. 

[Guppysnail]

I have pothos, monstera peace Lilly and many others. Root size For me determines if I use the entire plant or cuttings. I rinse all the dirt off roots and leaves.  I use a mild vinegar water solution sprayed on the leaves for 30 seconds to dislodge residue and rinse. Then let roots soak in water for a day and rinse again to remove any remaining dirt from the roots. I have never had issues in any tanks. 

Edited November 7, 2022 by Guppysnail

[Expectorating_Aubergine]

On 11/7/2022 at 5:51 AM, gardenman said:

In the gardening world there are two major types of pesticides. Applied pesticides that are sprayed onto the plant and systemic insecticides that are added to the soil/water and absorbed into the plant. In either case if you give the plant a month or two and don't let the soil come into contact with your water, you should be okay. Some commercial greenhouses these days rely on other means to control insects. A common technique is to fill the greenhouse with CO2. Plants love CO2 but insects tend to have a hard time breathing it. By sealing a greenhouse and bringing the CO2 level up to 1%-2% (or higher) they can both enhance plant growth and destroy many/most insects. This is done mostly on the commercial level as workers in those greenhouses with elevated levels of CO2 need to wear oxygen tanks while the supplementation is ongoing. In some cases, they'll temporarily vent the heater from an adjoining greenhouse into the one they wish to treat and the CO and CO2 from the exhaust gases will serve to suffocate any insect issues at essentially no cost. Once the desired exposure time has been reached, they'll then vent the greenhouse before letting workers back in. Pesticides are expensive, so most growers only use them when necessary. In most cases a plant produced in a large commercial greenhouse should be relatively free of any pesticide that can harm your tank or fish.

I've actually done this with terrariums when we get meat delivered to the house (comes packed with dry ice), and it works pretty well. 👍