What Should I do

So I made a 5 gallon batch last night, first time all grain, with grain that has been milled for about a month and yeast that was 6 weeks old (wyeast package) and I had some wort left over so I made an experimental 1 gallon batch as well with yeast I had previously harvested. The 1 gallon batch took off with the harvested yeast and is fermenting nicely, but the 5 gallon batch still did not. It has been 24 hours and still no signs of fermentation, and I know it is too early to start worrying, but if it doesn't take off could I add the 1 gallon batch into the 5 gallon with 2 different yeast strains combining or would this create some mutant frankenstein ale. Thanks

I have had beers take almost 3 days to take off. I would wait that amount of time and check the gravity to make sure nothing is happening. If the gravity isn't moving, pitching the 1 gallon batch in there should be fine as the dominant yeast should take over.