When to plant tomato? This is a good question . The tomato is such a good plant to grow because it gives and gives and gives. Little effort with lots of reward. When the maple tree leaves have fully opened, it is safe to plant your tomato. But be smart about it. Only plant what you need because they can get ahead of you make a huge mess . Of you find you have over planted and exhausted all your friends and family then contact your local food pantry or soup kitchen .