Don't leave them soaking for more than 24 hours or they could grow fungus. Once the seed is cracked go ahead and plant it. Waiting for the tap root to grow can cause fumbling hands to snap it off. Happens to me to often. I wait for the seed to crack and point it with the tap root pointing down. If the seed cracks you have a pretty good chance of it growing. No need to let the tap root grow out of the seed unless you have steadier hands than me.