Monty Don Reveals: 10 Gardening Mistakes You Don’t Realize You’re Making—#7 Could Ruin Your Plants

Monty Don, a beloved gardening expert, has dedicated his career to helping gardeners cultivate healthy and thriving gardens. However, even the most experienced gardeners make mistakes—sometimes unknowingly—leading to poor plant growth, disease, or even plant death.

If you want a flourishing garden, avoiding these common mistakes is crucial. In this guide, Monty Don highlights 10 gardening mistakes many people don’t realize they’re making—and mistake #3 is so critical it could completely ruin your plants!

1. Overwatering: The Silent Killer of Plants

Watering is a fundamental part of gardening, but more water doesn’t always mean healthier plants. Overwatering is one of the most common mistakes gardeners make, leading to root rot, fungal diseases, and weak plant growth. Plants need oxygen at their roots, and excess water displaces air pockets in the soil, suffocating the roots and causing them to rot.

Signs You’re Overwatering:

• Leaves turning yellow and falling off
• Mushy or blackened roots
• A foul smell coming from the soil
• Mold or algae growing on the soil surface

How to Avoid Overwatering:

Instead of following a rigid watering schedule, always check the soil moisture before watering. Insert your finger about an inch into the soil—if it feels dry, water the plant. If it’s still damp, wait a few more days. Deep watering less frequently encourages deeper root growth, making plants more resilient to drought conditions.

2. Ignoring Soil Health – The Foundation of a Thriving Garden

Soil is the lifeblood of your garden, yet many gardeners overlook its importance. If your soil lacks essential nutrients or has poor structure, your plants will struggle to grow, no matter how much care you give them. Healthy soil provides a balanced mix of nutrients, water retention, and proper drainage.

Common Soil Mistakes:

• Using the same soil year after year without adding organic matter
• Failing to test soil pH, leading to imbalances
• Walking on garden beds, which compacts the soil and limits root growth

How to Improve Soil Health:

Regularly add compost, aged manure, or organic mulch to replenish nutrients. Test your soil’s pH and nutrient levels each season to determine what amendments are needed. Also, avoid stepping directly on garden beds, as compacted soil makes it harder for roots to spread and access nutrients.

3. Pruning at the Wrong Time – This Could Ruin Your Plants!

Pruning is an essential part of plant care, but doing it at the wrong time can result in weak plants, fewer flowers, or even plant death. Different plants require pruning at different times of the year. Cutting plants back at the wrong time can remove essential buds, reduce flowering, or expose plants to disease.

Common Pruning Mistakes:

• Trimming spring-flowering shrubs in winter, which removes the buds needed for the next bloom
• Pruning fruit trees too late in the season, leading to disease and reduced fruit production
• Cutting back bulb foliage too soon, stopping the plant from storing energy for next year

When and How to Prune:

• Spring-flowering shrubs (lilacs, forsythia, camellias) should be pruned immediately after they finish blooming.
• Summer-flowering plants (roses, hydrangeas) should be pruned in late winter or early spring before new growth starts.
• Bulb plants (daffodils, tulips) should be left alone until all the green foliage has naturally died back—usually by June.

4. Planting Too Deep or Too Shallow

How deep you plant flowers, shrubs, and bulbs directly affects their health and survival. Too deep, and they might not sprout; too shallow, and their roots can dry out or get damaged by extreme temperatures.

Common Mistakes:

• Burying bulbs too deep, preventing them from sprouting properly
• Planting trees and shrubs too deep, which can lead to stem rot
• Planting too shallow, leaving roots exposed to sun, wind, and fluctuating temperatures

How to Plant Correctly:

• Follow the twice-the-bulb-depth rule (e.g., a 2-inch bulb should be planted 4 inches deep).
• Trees and shrubs should be planted at the same depth as they were in their nursery pots.
• Mulch around plants to help retain moisture and protect roots.

5. Using the Wrong Fertilizer or Over-Fertilizing

Fertilizing helps plants grow, but too much or the wrong type can actually damage your garden. Over-fertilizing can cause burned leaves, stunted growth, or reduced flowering.

Signs of Over-Fertilization:

• Brown, crispy leaf edges
• Excessive leafy growth with fewer flowers
• A buildup of white crusty residue on the soil surface

How to Fertilize Correctly:

• Use organic fertilizers like compost or aged manure for slow-release nutrients.
• Match the fertilizer to the plant’s needs—nitrogen for leafy plants, phosphorus for flowers, potassium for root development.
• Fertilize only during the active growing season and avoid excessive use.

6. Not Considering Sunlight Needs

Different plants require different amounts of sunlight. Placing sun-loving plants in shady spots or shade-loving plants in full sun can lead to weak growth and fewer flowers.

Common Mistakes:

• Growing roses, tomatoes, or peppers in too much shade
• Placing ferns, hostas, or impatiens in direct sunlight, leading to scorched leaves
• Not taking seasonal sunlight shifts into account

How to Get Sunlight Right:

• Observe your garden’s sun exposure throughout the day.
• Choose plants based on their sunlight requirements.
• Use taller plants or trellises to create shade for delicate plants.

7. Failing to Mulch Properly

Mulching helps retain moisture, suppress weeds, and regulate soil temperature, but improper application can harm rather than help.

Common Mulching Mistakes:

• Piling mulch against plant stems, causing rot
• Using too little mulch, which doesn’t effectively suppress weeds
• Choosing the wrong mulch, which can deplete soil nutrients

Proper Mulching Techniques:

• Apply 2-3 inches of mulch around plants, but keep it away from stems and tree trunks.
• Choose organic mulches like wood chips, straw, or compost for added nutrients.
• Replenish mulch each season to maintain effectiveness.

8. Ignoring Weeds – The Silent Thieves in Your Garden

Weeds compete with plants for water, nutrients, and sunlight, leading to poor growth and reduced yields.

How to Control Weeds:

• Pull weeds before they flower to prevent seed spread.
• Use mulch to suppress weed growth naturally.
• Try organic weed killers like vinegar spray for non-toxic control.

9. Forgetting to Rotate Crops

If you grow vegetables, planting the same crop in the same spot year after year depletes the soil and invites disease.

How to Rotate Crops:

• Change planting locations each season to maintain soil health.
• Avoid planting the same plant family (e.g., tomatoes and potatoes) in the same spot.
• Use cover crops in winter to restore nutrients.

10. Not Giving Plants Enough Space

Overcrowding plants reduces air circulation, increases disease risk, and causes nutrient competition.

How to Space Plants Correctly:

• Follow spacing guidelines on seed packets.
• Thin out seedlings if they sprout too close together.
• Consider vertical gardening to maximize space.