Stem Rot on Hygrophila corymbosa.

[Ozzie Boss]

I bought some plants a month ago for my tank. They were grown out of water so I expected them to melt back to grow in water. However after 2 weeks when I bought them I noticed the stems of the plants turning black. The plant then start moving with the water flow until the whole stem was black and died off. I lost 2 stem plants because of this. Now my other hygro plants are starting to do the same thing. What is happening? Other plants I have in this tank are wisteria and Cryptocoryne Becketti, and they are doing fine. The substrate is sand. I dose 5 ML Seachem Flourish 2 times a week ,and I have the light on at 8 in the morning to 9 at night.

Other info:
Nitrate: Around 0-20
Nitrate: 0
pH: 7.5
KH: 60
GH: 180

Stocking:
3 Juvenile Angelfish
7 White Skirts
5 Emerald Green Corys

Water Changes:
50 Percent every 2 weeks.

Tank Size:
50 Gallons

 

[Colin_T]

If the stems get damaged they will turn black and rot. You should use a clean sharp pr of scissors and cut the stem about an inch above the rotting part. If possible cut the stem about 1/2 inch below a leaf node (where the leaves come out of the stem). Then carefully replant the plant in the substrate.

 

[Ozzie Boss]

Okay thanks I just did that. What causes the stem to become damaged? And how do I prevent it?

 

[Colin_T]

The stem is usually damaged when people plant it in the gravel. Quite often people will push the plant into the substrate and that can damage it. The best way to plant cuttings is to dig a hole and hold the stem in place, then fill in around the stem.

If the stem gets squashed while packed then it will rot too. There's not much you can do about this except hope the supplier is packing them carefully.

And if the supplier uses a dirty knife or cutting implement, the wound where it was cut can become infected and rot. Again, there is nothing you can do about this except hope the supplier is not lazy and careless.

 

[Ozzie Boss]

Ahh that explains it. I think I damaged it when planting as it was my first time planting. I was under the assumption that it was a lack of nutrients in the sand and lighting. Thank you.