Leaving abundant space in a flower bed or vegetable garden is not very useful if you’re trying to be a laidback gardener: weeds will quickly move into any open space. Instead, you should try to plant so that all the space is filled with greenery, yet while leaving enough room for the plants to reach their full size. That means each plant needs to touch its neighbors on all sides, yet still have enough room for healthy growth.
That’s why you should consider planting a bit tightly, at about three quarters of the plant’s mature size.
Thus, a perennial that reaches 30 inches (75 cm) in diameter at maturity could be planted with about 24 inches (60 cm) spacing in mind (this isn’t rocket science: round up or down a bit as needed). And a shrub that will attain 4 feet (120 cm) in diameter could be grown using 3 feet (90 cm) as its ideal spacing. Soon your flowerbed will be 100% full … but not overcrowded: your plants will still have the space they need to develop.
The French Intensive Method
Do the same in the vegetable garden. Leaving a wide inter-row between each row of vegetables, as is done in the traditional vegetable garden, is an outright invitation to weeds. It’s like saying: come on in, I left you plenty of space!
Instead, when you check a seed packet and it says to leave 6 inches (15 cm) between the plants and 16 inches (40 cm) between the rows, just ignore the second number. Plant at 6 inches (15 cm) between plants and between the rows.
Now, you will need access to the garden, so do leave an occasional inter-row (an empty row you can walk in), but only about every 4 to 5 feet (120 to 150 cm) apart, so you’ll have full access to the garden. Make that inter-row a permanent path and mulch it abundantly to make it as inaccessible to weeds as possible.
This is known as the French intensive method of gardening: more vegetables in less space, but with fewer weeds. It’s a win-win situation!
When you sow or plant your flowers and veggies so they’re spaced just a bit on the tight side, the plants will be happy and you’ll be happy. It is only the weeds that will be upset!