Why does my raised bed stay waterlogged after rain?

Either could be relevant, and the visible water pattern can help you describe the problem. Slow drainage can occur in compacted or clay-rich soil, above a less-permeable layer, or where the bed soil meets underlying soil with a different texture. [S1] A bed’s base matters too: a barrier can impede infiltration, and a raised bed on a non-soil surface has different drainage considerations from one set directly on soil. [S2]

Those are general explanations, not a way to identify the cause in your particular bed. Start by noting whether water stands across the whole bed or in one spot, how long it remains after rain, and whether the bed sits on soil, paving, or another surface. Avoid changing the bed based on a single observation.

Make a simple raised-bed drainage worksheet. For the construction, write down the bed’s approximate length, width, and depth; what it is made from; whether it has a bottom; and what you know about any fabric, liner, or other layer beneath the growing soil. Mark whether the bed sits on bare ground, paving, or another surface. If you do not know what is underneath, write “unknown” rather than guessing.

Then describe the growing soil and the ground around it using observations, not conclusions. For example, record whether the soil looks compacted, whether water collects at the edges, and whether nearby ground is also wet. Note where your information comes from—your own observation, a prior note, or an estimate. This helps keep confirmed details separate from assumptions.

Use the same observation points each time: date and approximate rainfall conditions; where water is visible; whether it is pooled or the soil merely feels wet; and how long after the rain you checked. A quick sketch can show standing water in the center, along an edge, or across the bed. Record what you see at a consistent interval when practical, and note if another rain fell before your next check.

For instance, an explicitly hypothetical entry could read: “Example only — Bed A; rain overnight; shallow water in the back-left corner at morning check; no visible pooling at the front edge; checked again later that day; another shower occurred before the next check.” This example does not imply any particular cause. It shows how location and intervening weather keep observations interpretable.

Colorado State University Extension describes a check using a 12-inch-deep hole filled with water: failure to drain in 30 minutes indicates a drainage problem, and water remaining after 24 hours may affect plant growth. [S1] That is general Colorado guidance, not a diagnosis of your raised bed; it does not establish the cause of waterlogging, and conditions elsewhere may differ. Consider regional growing guidance before using the result to choose a change.

Take your worksheet to a local gardening educator or regional extension service if you need help interpreting it. Useful questions include: “Does the bed appear to sit on a drainage barrier or contrasting soil?” “Would this check be relevant to my site?” and “What local guidance applies before I alter the bed?” If the underlying layer or construction is unknown, say so; the notes are still useful without a firm conclusion.