How to Tell How Many Plants Can Fit in Your Garden Before Spending Money

Spacing out your plants is important for their seeds to germinate and roots to grow, but depending on how much space you have and the plants you’re looking to grow, it’s hard to tell just how far apart they need to be. Thankfully, there are tools to help you figure it all out before you start your next garden project. Here’s how to calculate the perfect spacing for your row of new plants.

Why is spacing plants important?

“Room to grow” is a common saying for a reason: Not only do roots need room to stretch, but the airflow around plants is crucial in preventing plant diseases and fungi from spreading.

Spacing is vital in the wet and humid months in particular, like in the fall where fungi like to spread. Rocket Gardens explains how airflow is particularly important for “spore carried diseases, like blight and mildew, as well as things like chocolate spot on broad beans.” Proper spacing also allows leaves to grow and capture as much sun as possible.

How to find the right spacing for your garden

The space you need between seeds depends on the type of plant and its expected size at maturity, which is usually found on your plant’s growing guide and seed packets. In general, you’ll want to space plants as far away as the full radius of the plant at maturity.

For example, as Love to Know explains: 

A tree that is expected to grow 12.19 m wide would be planted 12.19 m from the next tree of the same variety.

It gets more complicated if you’re mixing different varieties to the point where you’ll need to split the difference of each plants’ radius, but Gardening Know How offers a spacing guide for vegetables, and Better Homes and Gardens has a good spacing guide for perennials. After you’ve figured out the proper spacing, you can better decide how many plants you want to buy.

How to calculate the number of plants for your plot

The site Omni offers 1940 calculator functions, and one of them is great for helping you find the perfect spacing for your garden. The plant spacing calculator accommodates whichever configuration you want, whether you’re planting in a triangle, seeding in rows, or planting flowers in a box — you’ll just need to know the size border you’ll have around the plant bed, the length, and the width before using it. Once you plug in the data though, the calculator will give you the exact number of plants you’ll need for perfect spacing.