mine was already cycled. was an established tank i converted. yes i planted right away . very heavy plant load in my tank. Some that grow quick to absorb extra goodies from water column and some heavy rooters to break up the soil and release bubbles. i use a chopstick sanded down to a fine point to poke gravel, anything will work as long as it doesnt release too much back into tank.
i also have assassin snails in my tank which are burrowers and will also help, like i said i got bad dirt from the start from everyone elses opinion but i am sticking with it and so far so good . everything perfect with awesome growth .