Mold chipping stain on deck?

Here is a link that might help you, it talks about how to clean and maintain a mold free deck:

https://www.klassicdecks.com/how-to-remove-and-prevent-mold-and-mildew-on-wooden-decks

A cup of vinegar in a gallon of water should take care of the mold. If the mold keeps growing, you may need to move the umbrella occasionally, so the area can dry out.

Vinegar and water to clean the mold like Ann suggests. Vinegar kills mold spores. You can place shims around the edges of the stand just to elevate it a little to allow air movement underneath. A 1/4" gap would be enough

Hello. We were amazed with the product wet and forget. It removed mold and mildew stains from areas quite high on our house siding. We would’ve had to hire someone to treat these areas as not to have to use a ladder to pressure wash.

It has a preventative nature built into it it might be something you might want to consider for your deck cleaning and care. In this link below it mentions it can prevent these mold mildew LJ problems for up to a year.

http://www.wetandforget.com/blog/2019/05/03/how-to-clean-decking/

Here are some tips on how to prevent mold from growing on a deck: https://www.youtube.com/watch?v=RQ44AOITtdM

you could cover the bottom in a felt type fabric that won't fade onto the deck you can buy it in sheets at places like Home Depot in the aisle where the pads are for chairs

Wet & Forget Outdoor is a good mold and mildew inhibitor. It's the only thing that stopped our front porch steps from being covered in slime if I didn't scrub weekly.

I would spray the area with mold killer and then use a power washer to clean that area and see if that helps. Also, you could move your table and umbrella for a bit and let UV rays beat down on that area of the wood to also help kill the mold. Then use a sealer on your whole deck to prevent this in the future.

Once the deck is thoroughly cleaned and dry, we recommend applying an inhibitor such as the 30 Seconds® Spray and Walk Away. This product is activated when it gets wet (i.e. when it rains) and helps to keep the mold growth at bay for longer periods of time; therefore, fewer cleanings are required.

it needs to be lifted off the deck since it sits flat on the deck any moisture will cause mold

you could put small feet on the bottom of the umbrella stand to lift it up they sell them at HOme Depot they come in all shapes and sizes