Low OG

Okay, still new at this and starting my third batch. First 2 are drinkable so far but this time I'm doing five gallons using a different juice. My first 2 I used Indian Summer Apple Juice, this time I'm using Indian Summer Apple Cider (which I had intended to use in the first 2 batches but the store only had juice).

In any event, my OG in the first 2 batches with the juice was 1.051 and fermented down to an FG of 1.005 which was about where I wanted it.

Today I got setup for the cider batch and my OG is 1.035 which seems low. Is it?

Yep. I'd add sugar.

That's pretty low imo. If you want a higher ABV boost the juice with your sugar of choice. White or brown sugar, concentrate, honey etc are all popular.

I like my ciders to be in the 1.050-1.060 range with natural apple fermentables. Too much additive sugar quickly changes the character of the beverage.

Thanks for the help. Can I let it ferment out as is and THEN add the sugar/honey/concentrate if its too low to restart it?

You can add ferment able sugar throughout the process. Why not add you concentrate or sugar now though? If your primary is full just pull some juice out and mix it.

Better to add it at the beginning and lessen the risk of aerating the cider and causing oxidation due to splashing/mixing later on.

Thanks guys. Added 3 pounds of cane sugar & brought it up to 1.056. Yeast pitched. We shall see.

Correct me if I'm wrong, but oxidation shouldn't be a major risk if the cider is still fermenting fairly actively (like after you put sugar in provided the yeast hasn't already hit its limit). Some people even intentionally whip up their cider at the start to introduce additional oxygen to help the yeast get a start.
Its more of an issue once fermentation is finished.

I'm a little confused about oxidation. It seems to me any exposure to the atmosphere will produce oxidation; isn't that why cider tends to have a tannish/brownish color anyway? Or is this another type or phase of oxidation?

Fresh apple juice gets oxidized during the grinding and pressing process, which is why it's brown. It doesn't take much to change the color of that raw juice, I'm sure we've all seen how fast an apple browns when cut in half. Oxygen in the juice prior to fermentation is a good thing. The yeast needs a certain amount of it to develop healthy cell membranes. Once fermentation is going though, watch out! Those same yeasts are anaerobic and want to live in a reductive environment. Additionally, when alcohol and oxygen react, they form acetaldehyde and increase volatile acidity of the cider . . . vinegar anyone?

Next time you open a bottle of wine or cider, leave some open on the counter overnight. Taste it and you'll notice a significant dulling the the flavors.

Cider-air surface contact will certainly cause a small amount of oxidation, but once fermentation starts it creates a blanket of CO2 which protects the product.