I think pine does not have a long life as an outdoor table. It doesn’t matter which “sealer” you used. Pine is often used for framing, indoor furniture, but not for long life outdoor uses.

Google: woods for wet environments

Pine and water/harsh weather do not mix. If your heart is set on pine, you can stain it or leave it in the current color, but polyurethane using an "outdoor" poly such as made by Zar, Watco, Valspar, etc. Apply three coats, using the brush type as specified on the can, and insuring you're doing this in appropriate temperature and humidity conditions. Make sure you poly every nook and cranny, including leg bottoms, underside, between wood pieces, etc.

Always allow adequate time between coats, to avoid tackiness.

Oilbase generally lasts longer but requires a longer dry time between coats. Additionally, you need cure time, meaning you don't want to finish three coats of poly then immediately subject the table to heavy rain or snow. Will this table set on a patio, or upon grass/ground? I'd elevate it atop something for the winter where it can't wick/holdwater.

Hi, and thank you so much!! I already purchased the table--not really bc my heart was set on it or anything, but because my husband wanted a picnic table at the back of the yard & the pine one that the Home Depot sold was the only affordable one. Right now it's sitting at the back of the yard + I'm worried b/c we had a very light rain the day it arrived (just 2 days ago). However, we currently have a heat wave (I'm in San Francisco). I will go and put deck stain on it now so it has some color. After that, I'll buy one of the polyurethane products you suggested + I'll be sure to wait between coats. I do have one question though: It's just sitting on dirt. What can I use to elevate it? I can't really move it anywhere as it is crazy heavy. Should I buy some bricks and place it on that, or is there some easy thing you can think of that I can get at the Home Depot or Lowe's to sit it on? I'll also put a tarp over it for the winter months. Thank you so much!!

I have a cedar log swing in the back yard. I put the legs on round patio stones to keep them off the bare ground.

You've discovered the problem with buying cheap stuff - it often doesn't last, and you have to spend money to replace it. You are on your second picnic table, and about to spend more money to protect it from the elements.

Start saving now, so when this table crumbles, you can replace it with one that will last. Remember that sunlight is as harmful to outdoor furniture as rain.

@Jeanine Kitchen Remodel -Because you're in San Francisco, I doubt you'll need more than 2B gravel or similar to keep water from pooling around the legs of your table. I can tell you that if you are friends with a cabinet maker and they have some blocks of mahogany or teak wood upon which to set the table legs, it would really help you out. Even the bricks that Ann KH suggested would work in your climate. Cedar or teak are more suitable to areas where water can otherwise be a problem, and although costly, will afford a long lasting table. Hope this works for you.

Thanks everyone! :))