How excessive rainfall affects your garden


I hope this e-mail finds you safe and sound during this challenging time for our area. Many people are still without electricity. Others are dealing with destruction to their homes and landscapes. To top it all off, the rain just won't stop.

Here's how this excessive rainfall might be affecting your garden:

  1. Soil erosion.
    Heavy rainfall and flooding can wash away topsoil, exposing root systems and reducing plant stability.
  2. Root damage and plant stress.
    Saturated soil can deprive plant roots of oxygen and essential nutrients eading to plant stress. Signs of water stress include yellowing leaves, wilting, stunted growth, and even plant death.
  3. Nutrient leaching.
    Too much water can leach nutrients out of the soil, reducing overall fertility and stunting growth. The leaching effect is generally most pronounced with nitrogen.
  4. Pest and disease proliferation.
    Prolonged dampness in the garden encourages fungal disease. Plants stressed by adverse conditions are also more prone to pest damage. Moisture-loving pests like slugs and snails can become more problematic.
  5. Reduced fruiting.
    Pollen is very sensitive to high heat and high humidity levels. When the average temperature rises above 95 degrees during the day and 75 degrees at night, or when humidity levels are extreme, pollen loses its viability. Without proper pollination, flowers cannot produce fruit. The result is blossom drop and lowered production.

What you can do about it:

  1. Address drainage issues in your gardens and landscape.
    Identify where water is pooling or left standing after heavy rains. Raise the elevation of landscape beds by adding topsoil and compost prior to planting. If water pools in turf, raise low areas by adding topsoil or consider installing a French drain. Other options include building swales and rain gardens.
  2. Plant in raised beds.
    Raised beds can be constructed with lumber or stone, but you can also create raised beds by simply mounding up the soil so that the garden bed soil is higher than the surrounding area.
  3. Improve soil drainage with compost and expanded shale.
    Heavy clay soils drain poorly. To improve drainage in clay soils, amend soil with 3 inches (by volume) of good compost and 3 inches of expanded shale. Mix into the soil to a depth of 6-8 inches. (Calculator for estimating material requirements.)
  4. Mulch.
    Mulch is the Swiss Army knife of garden supplies. It performs a multitude of tasks. Mulch not only retains moisture during dry periods, but it can also prevent your soil from becoming waterlogged and reduce erosion. It also lessens disease pressure by preventing soil from splashing up onto plants. Never leave soil exposed anywhere in your landscape. Maintain a 3-inch layer of mulch at all times.
  5. Choose native plants and match plants to soil moisture requirements.
    Native plants are more resilient and adapted to local weather patterns. Because different plants require different soil moisture levels, always be aware of an area's soil characteristics (i.e. more dry on average or more wet on average) before buying plants. For example, Texas Sage shrubs fail to thrive if soil doesn't drain well or retains excess moisture.
  6. Space plants properly.
    My tomatoes look pretty good right now considering these wet conditions. Much of that comes down to variety selection, but it's also because I've given them plenty of space (at least three feet between plants). Never plant anything without knowing the recommended spacing. This can be found on plant labels or through a quick Google search. When direct-sowing seeds, remember that you MUST thin them out to proper spacing once they get their first set of true leaves. (When a seed germinates, the first leaves to emerge are seed leaves that will eventually fall off. The second set of leaves are "true" leaves.)
  7. Keep fertilizing and watch for deficiencies.
    A sign that your plant needs fertilization is yellowing of leaves or overall pale coloring. (Nitrogen is the most common deficiency here in North Texas. Our soils are generally sufficient in phosphorus and potassium.) If you need to quickly rectify a nitrogen deficiency, apply fish emulsion 5-1-1. It's a fast-acting, organic source of nitrogen for plants. If you've been using a fertilizer regularly up until this point, stay consistent with the application frequency recommended on packaging.

In case you missed it, I just released a brand new video course: Plant Propagation: Cuttings, Layering and Division. It's the perfect way to build your skills while sitting out the next rainstorm. After taking this class, you'll be able to confidently and endlessly make new plants from existing plants in your garden. Warning: It's addicting! Propagating with cuttings is also an excellent project for kids. Get them to help you monitor growth progress and compare success rates between various mediums. Experiments abound!

The course is just $19 and includes unlimited access to help and guidance from me.

Let's keep our fingers crossed that some relief from this rain is in our near future.

CWL

The Dallas Garden School

By teaching you how to connect deeply with nature, The Dallas Garden School helps you unlock your full potential. Callie is the foremost gardening expert and educator in North Texas and a gardening columnist for D Magazine. Based in Dallas, Texas.

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