Common Veggie Garden Problems (And how to fix them)

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Eat your veggies! They are so good for you. It is nice to get them from your local grocery store but even better to pick them out of your own garden. Nothing like the smell and taste of fresh veggies! Nothing like the satisfaction of knowing you grew them on your own! Nothing like the joy of sharing with family and friends! Nothing like a good ole’ disease to rain on your bountiful vegetable parade! It’s just like me to be a “Debbie Downer”, isn’t it?! It would be great if we could just yell at the disease and it would go away. It is not quite that simple but I do have some solutions for you.



Cercospora Leaf Spot:

  • The disease lays dormant in old affected leaves left in the soil of the garden bed.
  • It spreads quickly by wind, splashing water, and leaf to leaf contact.
  • Water is necessary to activate the disease.
  • Lesions on leaves are somewhat circular, yellowish at first, and have a white to tan center with a dark halo around the spot. Spots will dry up and turn into holes.
  • Bottom leaves will be affected first, turn yellow and drop off the plant.

Cercospora Leaf Spot Control:

  • Remove infected leaves & throw them into the garbage.
  • Do not overcrowd plants.
  • Avoid overhead irrigation. Water spreads the disease.
  • Spray immediately with Copper Fungicide by Bonide. Make treatments weekly.
  • Fertilize monthly with Espoma’s Garden-Tone + Van Wilgen’s Fish & Seaweed weekly(especially in this heat) to keep plants healthy.
  • Clean garden beds thoroughly in the Fall. Do not leave any dead leaf debris in the garden.
  • Throw infected plant debris away in the garbage, not into your compost pile.


Septoria Leaf Spot:

  • It begins on the lower leaves of the tomato plant.
  • The disease remains living in old tomato plant leaves.
  • Spots appear as water-soaked circles with grayish centers, a dark brown margin, and little black spots in the middle.
  • Spots will eventually dry up and leaves will drop.
  • It is spread by wind, rain, insects, cultivating, etc.

Septoria Leaf Spot Control:

  • Remove infected leaves and throw them away in the garbage.
  • Avoid overhead irrigation.
  • Fertilize tomatoes with Espoma’s Tomato-Tone monthly + Van Wilgen’s Fish & Seaweed weekly to keep them strong.
  • Spray weekly with a fungicide, such as Daconil, Copper, or Serenade.
  • Do a complete garden clean-up in the Fall and remove all infected vegetation.
  • Rotate your crop yearly to a different location in the garden.


Powdery Mildew:

  • This disease shows up on leaves of squash and cucumbers in a blotchy form or a full covering.
  • The fungus is white to gray in color.
  • It weakens the plant significantly to the point that you may not get any maturing fruit.
  • If the fungus completely covers the leaf, photosynthesis will stop, the leaf will turn yellow and drop off the plant.
  • It remains to overwinter in affected cucumbers and squash.
  • In the Spring, it is spread by wind, insects, rain, birds, etc.

Powdery Mildew Control:

  • Be sure plants have good air circulation and are not too crowded.
  • Water plants at the base, not from the top.
  • Pick off and throw away infected leaves.
  • Treat weekly with a fungicide. Daconil, Safer’s Garden Fungicide, and Copper will all do the trick.
  • Fertilize monthly with Espoma’s Garden Tone monthly + Van Wilgen’s Fish & Seaweed weekly to keep plants healthy and strong.
  • Clean up the dead plants in the garden at the end of the year. Fungal spores will remain in the dead leaves and reinfect plants next season.

Hopefully, I was not too much of a “Debbie Downer” in this tip. Let’s look at the bright side of things. Rarely do these diseases kill the plant and you will still enjoy some delicious vegetables as long as you follow some of the control measures above. Now I am more of a “Penelope Positive”, don’t you think?!

Come see us at VanWilgen’s. We would love to help!