Why are some of my plants yellowing?

[knitter4democracy]

We put in new square foot planters this year (four of them), and a couple of my tomatoes and watermelons have yellowing leaves. Could it be the cold we've had this last week, or could they be overwatered with too much rain? I noticed it particularly last night, as one of the Early Girls is more yellow than green with one tomato growing on it already. Maybe it just isn't a healthy plant? I don't know what to do to help them out.

[crispini]

1. Possibly nitrogen deficiency

You can buy fertilizer, especially composted guano, manure, etc. You could pick up some stall litter from any nearby stables, but you'll need to compost it first. Or, use your pee! :) Make sure to dilute the urine first, though, that's a very concentrated source. More info here:

http://ezinearticles.com/?Using-Human-Urine-As-A-Liquid-Fertilizer&id=392596

[knitter4democracy]

4. I put fertilizer in the soil, though, before planting.

I got some of the Miracle Gro organic stuff on sale and put that all through the planter before putting the dividers on and the plants in. Should I try adding some ash to acidify it up just in the tomato squares?

[BOSSHOG]

2. Iron deficiency

most likely. A little shot of ironite should perk them up, but don't pamper them too much. Nothing will kill a plant faster then human attention and love. We just love em to death.

[knitter4democracy]

5. Our water has tons of iron in it, though.

They have been watered once. Heck, they'll probaby die of iron overdosing by the end of the summer.

[Dover]

3. This is from a Q & A page about tomatoes

42. Q. I planted the tomato varieties which you recommended and they are loaded with tomatoes. Now the leaves are beginning to turn yellow, then brown, then die from the bottom of the plant. What should I do; will this kill my plants?

A. You and everybody growing tomatoes are having the same problem. Tomato plants are developing brown spots on the lower foliage. This is the result of a fungus infecting the foliage causing a disease known as early blight. Early blight is an annual problem for most gardeners. It normally develops into a problem when plants have a heavy fruit set and the area has received rainfall. Spores from the fungus are spread to the lower foliage by wind and splashing rain. Leaves must be wet for infection to occur. At 50 degrees F. the leaves must be wet for 12 hours for infection, but at temperatures above 59 degrees F., the length of time for infection is only 3 hours. Leaf spot development is most severe during periods of cloudy days and high humidity. To control the fungus, foliage applications of a fungicide must be made every 7 days until moist conditions (dew included!) no longer exist. Applications should begin when the first fruit is slightly larger than a quarter. Chlorothalonil (Ortho Multipurpose Fungicide or Fertilome Broad Spectrum Fungicide) and mancozeb hydroxide (Kocide 101) are fungicides used on tomatoes for early blight. The copper fungicides also are affective against the foliage and fruit-infecting bacterial pathogens. Benlate (Greenlight Systemic Fungicide) should also be added every second spray application to prevent Septoria leaf spot. All listed fungicides can be mixed with insecticides or other fungicides except the copper-based materials (Kocide). The copper fungicides have a high pH which will reduce the life of many insecticides and some fungicides. Kocide is the only effective organic control for this pestilence.

http://plantanswers.tamu.edu/vegetables/tomat2.html



And a couple of more pages with Q & A about yellowing:

http://forums.gardenweb.com/forums/load/grtlks/msg0812523931785.html

http://www.thriftyfun.com/tf482428.tip.html

[knitter4democracy]

6. I don't remember seeing any brown spots, though.

I'll go look again and see. If that's what it is, would it affect the watermelon and cukes, too? They're also looking a bit yellow.

[hippywife]

7. What did you mix into your planters

to plant the tomatoes in?

[knitter4democracy]

8. I used the Miracle Gro organic stuff.

I put in less than they recommended (it sounded like a lot, and I knew I was getting great topsoil). Should I do something else?

[hippywife]

9. Is that fertilizer or

your growing medium?

[knitter4democracy]

11. Fertilizer.

I got some good topsoil from a local place I trust for the planters, but since it didn't have any fertilizer in it, I added some. Was that a bad idea?

[hippywife]

12. Well, when you said

you did the square foot thing, I just assumed that you did the planting mix recommended with that method and adding fertilizer gave the tomatoes more of something it didn't need more of.

I'm not a tomato expert but usually when most plants start yellowing I've always experienced it to be a sign of uneven water access. It goes too long without enough and them gets to much all at once.

[knitter4democracy]

14. Ah. That makes sense.

I was going to do the mix, but I got a good deal on this dirt, which is the same I have in the hole in the middle of our deck that we made into a planter that has been a very good spot for most anything.

The water thing makes sense. We got a ton of rain all at once that probably flooded the planter. I didn't water today, since the soil looked good still, but it'll need water tomorrow. I wonder if that will help take care of it.

[hippywife]

15. I would check it with your fingers

first and see how damp it feels and try to keep it consistent from here on out. Are you watering in the cooler part of the day, too? I usually water in the evening when the sun has dropped down toward the horizon a bit.

We did use the mix suggested with the square foot method and everything seems to love it!

[knitter4democracy]

16. I usually do water at night.

When I checked it today, it felt just right, but that means I should water it tomorrow. The straw mulch has helped keep more moisture in, but these things can dry out faster than I'm used to.

[knitter4democracy]

10. I took pictures today.

Here's one of the watermelons:

[Lone_Star_Dem]

18. It looks like a magnesium deficiency to me.

If I had leaves showing green marginal bands and interior yellowing that's what I'd assume they were hungry for. I'm leaning more that direction after reading about your heavy rains. Magnesium deteriorates quickly in the soil and in raised beds one heavy rain can leach it out.

However, it's easy and cheap to replace. Buy some epsom salts and sprinkle some around the plants.

[Lone_Star_Dem]

19. I forgot to mention above

On the melon. The true leaves look great. The first set of starter leaves look like they're just done doing their job and passing the torch off to the true leaves. Are you sure that's a watermelon? I kind of think it might be a muskmelon from the leaves. :shrug:

Also, if you are able take a soil sample into your county AG extension agent it's always a great help. They can check to see if your soil is in balance. If it's not they can tell you what you need to add to bring it around.

[knitter4democracy]

20. Ooh, I'll do that!

We have a good one, and I need to call them today about the fruit tree anyway. Maybe I should just go in with a soil sample and see what they think.

It's supposed to be a Crimson Sweet. I hope it's not a muskmelon--it's in my son's planter, and he's allergic to the darn things.

[Lone_Star_Dem]

21. Hmm. Watermelon leaves are usually deeply lobed...

Check out the image on this page. http://en.wikipedia.org/wiki/Watermelon

Sometimes I've had the first leaf be more heart shaped and less lobed on my watermelons. By the second leaf they're usually much more obviously lobed though.

Do you remember what the seeds looked like? Crimson Sweet watermelon seeds are small (1/8th inch or so) and dark brown/black. If the seeds he has are larger (near 1/2 inch) and a beige to cream color they're probably muskmelon.

You know that could even be a cucumber seeding. They look a lot like a muskmelon when they're small. :shrug:

[knitter4democracy]

22. D'Oh! It's a cuke.

I looked again last night. My son decided to put a cuke there instead of a watermelon. You're right, though--it does look like the older leaves giving it up to the new ones.

[wildeyed]

13. My peppers were looking a bit yellow.

I think they were missing micronutrients. I scratched in some kelp meal around the base, and that seems to have done the trick. Kelp meal, greensand or a good organic tomato fertilizer might do the trick for you. They all have micronutrients your plant might be deficient in.

[Dover]

17. Not sure, but maybe needs iron?

From that third link I gave you:


Question:
Can someone tell me why some of the leaves are turning yellow on my patio tomato plant? I would greatly appreciate an answer.
Hardiness Zone: 10a

mitch914 from South Texas

Answer:
Mitch,
Many insect and disease problems cause yellow leaves on a tomato plant. The problem could be cultural: too much water, not enough water, poor drainage, not enough sun, wrong ambient temperature, leaf scorch caused by dry, hot conditions following cloudy moist conditions (this can cause a sudden water loss in the outer portion of the leaves) or a build-up of salts from fertilizer.

It is hard for me to tell from your picture, but are any of the lower leaves turning yellow, or is it just the newer leaves? Do the leaves contain spots or rings? Do any of the following "yellow leaf" symptoms sound familiar?

Yellow or pale colored leaves: This could be caused by a nutrient deficiency. Here are some common symptoms:

Yellow with green veins = lack of iron
Yellow with dark spots and small, narrow leaves = lack of zinc
Yellow with green veins, turning bronze = potassium deficiency.
Yellow patches on leaves that contain brown concentrically ringed spots: This could be a sign of early blight. Spray copper or bordeaux mixture and repeat every 7-10 days.

Older leaves yellow; shoots (or whole plant) wilts: This could be Fusarium or Verticillium wilt. These two fungal diseases both begin with the wilting of lower leaves. The plants are stunted and do not recover when watered. When cut open, stems and shoots will show some internal discoloration. Toss affected plant and replace them with disease resistant varieties and new soil.

Leaves are yellow (may contain brown spots); leaves are also distorted and sticky: This could be a possible aphid or white fly infestation. Look for small sap-sucking insects (green, black, white, or pink in color) on the undersides of leaves and traces of honeydew on the leaves (sticky substance). Insects may also fly away when disturbed. Spray plants with a strong jet of water or insecticidal soap to remove.

Leaves are yellow; the plant is stunted and eventually wilts in hot weather: This could be a sign of Root Knot Nematode damage. Plants will have swollen galls on roots and eventually die. This is not as common in plants grown in new commercial potting soil.

Leaves mottled yellow; young growth appears narrow and twisted: This is most likely tobacco virus. Plants should be destroyed and replaced with a disease resistant variety planted in new soil.

Leaves speckled with yellow dots; fine webbing on leaves: Most likely spider mites. Spray them off with a strong stream of water from the garden hose, or use insecticidal soap.

I hope these ideas help!