wise, unless you have things such as a very acid soil and acid leaves. They will compost fully within the growing season, if the garden is well watered, they will bind and release nitrogen fertilizers, and form channels for fine roots if you have clay. In sand it would be less advantageous.
But why not use them for mulch? it will save you water later and effort now.

I agree that it all depend on the pH of your existing soil and the availability of nitrogen. Leaves are carbon based and most are acidic. So they can throw the pH out of whack temporarily and will bind up the soil nitrogen while they decompose IF they are tilled in. Often you will find you have to add lots of supplemental nitrogen for the plants.

Best result this close to planting is to use them as mulch on top of the soil as glib suggested. That way the soil N is available for the plants to use, not the leaves.

You'll find several discussions about this very topic over on the Soil, Compost & Mulch forum here including one long discussion from several members who tilled large amounts of oak leaves in in the spring last year and learned the hard way that nothing would grow.

Dave

Try as I might I could not find that discussion. Other parameters that matter: at this point my Fall leaves are about half still dry, and half have started to rot (they are in a pile). The rotting ones have their own N, and higher pH. Same if the leaves spent the winter mixed with other organic matter, such as kitchen scraps. These leaves should almost never present problems.

Dave is right that in certain circumstances you could end up with low N, but they are easily correctable. I tend not to notice these things because I add wood ash and urea as a matter of course, specially with urea I go by plant color.

In my case, adding fall leaves to the original native red clay always is welcome. I can take care of the "N"itrogen.
Adding whole leaves in the springtime might be a bit late. What you can do is to use your lawnmower as chopper. Close the shoot chut, take the bag out and run it on the pile several times. You need to do this when the leaves are fairly dry, not too wet. If you have a good crowd of workung worms in your garden, the broken leaves will become worm casting in a short time and you wont need micro organism slow process to decompose.

Leaves are organic matter, add them! I add in the fall and till them in. By spring they're about all composted! Just DO it!

Leaves are organic matter, add them! I add in the fall and till them in. By spring they're about all composted! Just DO it!

Adding them in the Fall is a totally different matter. The OP is asking about tilling them in NOW just prior to planting.

Glib - I'll see if I can dig up that discussion I referenced. It was just last fall so it should still be available on the servers.

frjeff - if you decide to do it just be sure to mix in lots of nitrogen rich supplements too.

Dave

Most of my leaves are oak leaves, I have 4 new raised beds going in, i was thinking of shredding them with a lawnmower and then putting them at the bottom of the beds then covering with compost and garden soil. They should decompose faster that way and worms will do the rest, right? I hate bagging and getting rid of leaves, but after 250 bags and probably another 100 id rather use them then bag them. Any thoughts?

Oak leaves are awfully acid and don't decompose as well as other leaves.

I would do it. They may hinder you a bit this year, but it can be corrected with lime and urea. Next year you will be well ahead with soil tilth and fertility.