Can I use grass in my garden after my seeds have sprouted and are growing as a mulch to keep weeds down, moisture up, and not worry about bugs and slugs?
Can Grass Be Used as Mulch in a Veggie Garden?
You can use grass clippings - read more here: https://www.gardeningknowhow.com/edible/vegetables/tomato/mulch-for-tomatoes.htm
More information about natural mulch: https://www.gardeningknowhow.com/garden-how-to/info/whats-the-best-mulch-for-my-garden.htm
Don't depend on the mulch to control pests, however. Many of them hide in the mulch during the day, and come out to dine at night. Foiling pests requires constant vigilance.