Tan Spots On Tomato

[joshuampascoe]

Hi everyone. Its my 1st year having a garden. I have about 15 tomatoes in pots and around half of them have tan spots on their leaves. I have no clue why. They are in equal parts peat moss, cow compost, lava rock. I have not fertilized. I water every 3 or so days. Any help is appreciated.

 

[Chuck]

I know of three reasons why your leaves are turning white. The first and most unlikely is sunscald. The second reason is insects of which I don't see any although mites are extremely small. The third and most probable is a lack of macro nutrients or NPK. Peat moss has no, that is zero NPK and in fact very little nutritional values at all. Manure based compost is a fantastic soil amendment and does have a good percentage of NPK but over time it leaches away, especially in containers. Lava rock or volcanic rock dust also has no NPK. What it does have is a LOT of needed trace minerals which your plants need. So, IMO what your plants need is to be fertilized, preferably with a good manure based ORGANIC fertilizer. All fertilizers leach but organic fertilizers actually adhere to soil particles so leaching is at worst minimal, the opposite of synthetic fertilizers.

 

[joshuampascoe]

Thanks Chuck. As for as organic fertilizer what would you recommend? My friend has a horse farm so I have an endless supply of manure, but none of it has been composted. Can I use the fresh manure to make a tea?

 

[Chuck]

Thanks Chuck. As for as organic fertilizer what would you recommend? My friend has a horse farm so I have an endless supply of manure, but none of it has been composted. Can I use the fresh manure to make a tea?

Yes, you can make tea from fresh manure. Any fertilizer with a OMRI rating is OK. Medina, Fox Farms, Espoma, Dr. Earth are but a few. If it has OMRI anywhere on the bag it will be fine. There are some unscrupulous marketers out there that advertize as organic but aren't. The OMRI rating assures you that it really is totally organic.

Be very careful when using horse or cattle manures. Many, many hay growers use a herbicide named Picloram on their hay fields. This stuff does not go away. It will go through the animal and still come out deadly to vegetable plants. A simple test is to put a shovel full of manure into a bucket of water, wait a couple of days and then go pour the water onto some broadleaf weed like a dandelion. If two days later the dandelion shows no ill effects the manure is OK.

 

[headfullofbees]

If the leaves shrivel, it is probable that your manure contains this steroid weedkiller.
Soil bacteria break it down, so if you let it rot down for a year, turning occasionally, it'll be fine.
We had the same problem here, where it was called "aminopyralid" & it was taken off the market.
Last year it re-appeared, & guess what? MORE CONTAMINATED GARDENS!!!
It would appear that either farmers just cannot be trusted with this, or, it contaminates the environment too easily.
Much of the problem also comes from animal bedding.