Why won’t my garden grow? 10 common plant problems

potted plants

My tomato plants were big and beautiful. I admired their vibrant green foliage and watched bees buzz between blossoms, eagerly waiting for fruits to ripen. But when I plucked the first tomato from the vine I made an alarming discovery: The tops of the tomatoes were firm and red, but the bottoms were sunken and black. Blossom-end rot had got the best of my garden.

Keeping a watchful eye on the garden throughout the season helps gardeners detect plant problems early, and apply effective solutions before it’s too late.  

10 common plant problems

1. Bulbs don’t produce blossoms. Bulbs that produce leaves but no blossoms lack nutrients. Apply fertilizer in fall and again in early spring to fix the problem.

All fertilizers are not created equal. Lawn fertilizer is not appropriate for flower beds. Purchase fertilizer specially formulated for flowers. An NPK ratio of 3-5-3 is ideal for perennial bulbs.

2. Wilt. Excessive heat and drought cause temporary wilt. If plants don’t perk up in the cool of the evening and early morning hours, wilt may indicate the presence of bacteria. Verticillium wilt affects pepper, tomato, eggplant and potato plants. Erwinia bacteria causes wilt in cucumbers, muskmelon, squash and pumpkin plants. Bacterial wilt will spread to healthy plants. Pull infected plants immediately to prevent total crop loss.

3. Mildew on foliage. Powdery and downy mildew affect a wide variety of plants: ornamentals, vegetables and trees. Gardeners can treat mildew diseases with fungicides, but it may be too late to save plants. It is best to pull infected plants immediately to prevent bacterial disease from spreading to healthy plants.

4. Stunted growth, low-yield and small fruit. Plants growing too close together will be stunted and produce less and smaller fruits. After direct sowing seeds, thin seedlings to provide plants with recommended space. Check the seed packet or nursery tag for space requirements.

5. Bitter tasting vegetables. Some cool season crops like lettuce become bitter as the weather warms. Bolted lettuce is tall and tipsy, and tastes bitter. Pull bolted plants and sow a second crop of lettuce when the weather cools in fall.

Growing cucumbers in drought conditions makes rinds bitter. Provide plants with 1 inch of water each week to promote good flavor.

6. Seeds don’t germinate. Good germination is a recipe with four ingredients: Fresh seed, warm temperature, adequate time and consistent moisture. Seed loses vitality each year after it is packaged. Purchase fresh seed packaged for the current season. Most vegetable seeds germinate at temperatures between 75 F and 80 F. Vegetable seeds germinate in seven to 14 days. Water with the goal of maintaining a moist potting mix.

7. Cracked tomatoes. Cracking may appear circular around the top of the tomato or vertical streaks from the stem. High nitrogen levels in soil and fluctuating moisture can cause cracking. Large fruited varieties like Big Beef and Mortgage Lifter are prone to cracking. Cracked tomatoes are safe to eat. Cracking does not affect flavor.

8. Deformed leaves and foliage. Deformed plants may be the result of environmental stress. Mechanical damage from mowers and poor pruning is another culprit.

Viruses also cause abnormal growth patterns. Viruses are often transmitted by pests. An example is yellow leaf curl virus that is transmitted by whiteflies. Implementing a pest management protocol early in the season is the best prevention.

9. Discolorations. Foliage discolorations may be due to insufficient nutrients in the soil. Purple foliage is a telltale sign of phosphorus deficiency. Yellowing may result from too little iron, manganese or zinc. A soil test will identify nutrient deficiencies and prescribe amendments. Contact your county Extension office to locate a reputable soil testing lab.

Orange rust is caused by fungal infection. Gardeners may notice rust on bramble foliage in early spring when the weather is cool and wet. Rusty leaves die and drop in late spring to early summer. Unfortunately, the fungus cannot be killed with fungicide. Remove the plants with roots and dispose of them immediately. Fungus will overwinter in diseased roots if plants are not dug up and removed completely.

10. Leggy seedlings. Short, strong seedlings indicate good health. Tall, weak seedlings are leggy. Legginess is the result of inadequate nutrients. Cole crops like cabbage and cauliflower are heavy feeders that often grow leggy when they lack proper nutrition. Feed seedlings with starter fertilizer or water with compost tea to remedy legginess.

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