Tomato leaf problem.

[EricKenney]

I am trying to grow a tomato plant for the first time under lights. I mixed my own potting mix out of 1 part compost, 1 part peat moss & 1 part vermiculite. After the plant sprouted I started using a 10:1 compost tea weekly. Shortly after starting to use the compost tea the tips of the leaflets started drying out but staying green. After awhile the edges turn brown. What am I doing wrong? Any help would be greatly appreciated.

[DoubleDogFarm]

EricKenny,

What type of light source are you using? Could it be to hot and burning the tips?

What is in the compost. Maybe it is to rich?


Eric

[EricKenney]

I am only using a 15 watt regular fluorescent above the plant and 2, 45 watt CFL growlights backlighting it. I keep the 15 watt light 2 inches above the plant and maintain a distance of about 6 inches on the CFL lights. The heat doesn't seem to be all that great around the plant. Only slightly warm.

[EricKenney]

It's mushroom compost that I'm using. I've read that it contains lots of nitrogen. I'm wondering if this could be the problem.

[EricKenney]

The growing tips are not affected. It's the oldest leaves on the plant that start showing this damage. This plant is still small, only 5 inches or so. apart from the leaflet damage the plant seems to be growing normally.

[applestar]

I have heard that mushroom compost is actually not that high in N because the mushrooms do use them up, but that it can be high in salt.

How much compost to how much water (before diluting for use)? and do you use rain water, dechlorinated water, boiled tap water or straight tap water? How long do you let it brew, and do you aerate? --Have you read the Compost Tea sticky thread in the Compost Forum?

[EricKenney]

Come to think of it, it does have what appears to be small areas of salt buildup on the underside of the leaves. I do use dechlorinated water. I fill my container about 1/3 full of compost, 2/3 full of water & I do aerate it. I brew it for 24 hours and use within 20 minutes of turning off the pump. Additionally, I put a small amount of unsulphered molasses and a small amount of cane sugar plus a very tiny amount of ascorbic acid into the mix. If it is salt buildup, will flushing the potting mix several times help?

[The Helpful Gardener]

Yes, but probably not in time for those maters...

Mushroom compost can still be pretty hot right after it is finished, and the microbial action can heat soils, and lock up nitrogen as well. It can also be acidic; that is the tendency of mushrooms. I would really like to compost mushroom soil for a while to ditch the salts and buffer the pH before using it as soil.

A test to tell salts (EC, or conductivity) and your pH would be interesting, helpful, and you can get them from your county ag extension service I bet... probably free, but certainly not much...

HG

[EricKenney]

Okay. I'll take a sample to my county extension office next week. I'll let you know the results. Thanks for the info.