Prevent Overwatering - Garden Pot Cover

Many flowering plants benefit from plenty of sunshine like the Red Mandevillas shown on the left. So it's sensible to locate them outside even if they're planted in garden pots. Having them outside though poses some problems when the rainy season comes.

Mandevillas simply hate being overwatered. Mandevillas have tuberous roots that already store water, and therefore watering needs to be done sparingly. I learned this the hard way way when one of my Pink Mandevillas died after receiving daily rains for five days.

Signs of Overwatering in Garden Plants

Here are some of the signs I noticed that indicated the garden plant was overwatered from the rains.

  • Shedding Leaves. Some of the leaves near the base of the plant started dropping even though they were still green and looking healthy.

  • Curly New Growth. The young leaves that were sprouting were curly and looked wilted. New growth in other branches halted.

  • Discoloring at Base of Stem. The lower stem near the base became grayish brown and looked mushy. When scratched with the fingernail, the outer layer easily peeled off revealing a gray colored cambium layer which should've been light green.

Prevent Overwatering of Container Plants

So, what to do when the soil of the garden pot has soaked and there no letup with the rains? For container plants that aren't permanently fixed outside (e.g., not trellised to wall), the obvious thing to do is to bring them inside. But this may not be practical, however. The plant may be too heavy or bulky. You want the garden plants to receive plenty of sunshine but to put them back in EVERYTIME it starts to rain - it is simply not feasible. If the garden plants cannot be taken in for shelter, the next best thing is to bring the shelter to the garden plants.

This could mean sheltering the garden plant pots with a cover. So for this project, we'll be making an improvised homemade garden pot cover. This will be customized to every garden pot that has a live plant growing in it. In the example below, the garden pot has TWO mandevillas growing in it.

Make an Improvised Garden Pot Cover

The main material to be used as a garden pot cover is an old dining table plastic placemat. The plastic placemat should be wide enough to cover the open top of the garden pot.

It should also be thick and durable enough to withstand the elements. Any other plastic material with suitable durability and dimensions will do.


  • Old Plastic Placemat
  • Measuring tape or ruler
  • 2-inch Nail
  • Vise Grip or Pliers
  • Candle
  • Scissors
  • Packing Tape


  1. Align the placemat horizontally with the top of the garden pot.

  2. Measure the plant's stem "coordinates" on the placemat and mark the coordinates on the placemat. This will be the position of the stem hole. For this project, the garden pot has 2 plants growing in it, so we measure and mark for 2 stem holes.

  3. Draw a 3/4" circle on each of the marked stem hole.

  4. Hold a 2" nail with a vise grip or pliers near the nail's head.

  5. Heat the pointed end of the 2" nail with a lighted candle as shown below.

  6. When the pointed end is hot enough, pierce the stem hole mark on the placemat to melt it.

  7. Expand the hole up to 3/4" diameter by continually heating the nail and melting the plastic.

  8. Cut a perpendicular slit from the edge of the placemat that is nearest to the stem hole. Cut the slit from the edge towards the stem hole as shown below.

    The slit is where the plant's stem is inserted and passed so it can be positioned in the stem hole. Shown below are the 2 stem holes and the corresponding slits.

  9. Lower one flap of the slit to insert the plant stem and pass it through all the way to position it in the stem hole.

    Be very careful when you do this as there is a big chance of wounding the plant's stem.

    Shown below is the garden pot cover positioned on top of the garden pot, with the two Mandevilla stems growing out of the two stem holes.

  10. You may leave the slits as they are or, alternatively, close them with packing tape.

Shown below is the garden pot with the cover as seen from above.

When the rains come, most of the rain water simply flows away from the top and trickle down the sides of the garden top cover.

Shown below is the garden pot cover as seen from below, during a rain.

Now, if you don't have an old dinner placemat that you can cut up for this project, you can use free and easily available materials for another homemade garden pot cover.

Go ahead, post your comment below!

Andrea said...

Hi Blackdove, i found you! I love the way your pot hang in there on brackets. I can imagine the watering chores you do during the dry season. So that is the red mandevilla, beautiful.

Andrea said...

I love your hanging pot, that last photo. Yes i wonder why you don't get comments! Maybe you are not visiting other gardening blogs too. Look at mine, I have many comments and gained many friends already. I am sure a lot of them will be interested in your posts.

Blackdove said...

Mandevillas are beautiful, but it's the the reds get plenty of comments from passersby.

I hardly visit other gardening blogs, other than when I need to research something.