Garden planting and transplanting is now in full swing and everything we want to grow can be planted out from now on.  It’s even not too late for planting of favorites like tomato & pepper plants, squashes, potatoes, onion sets, or greens.  But one question remains, which plants make good garden companions and which do not?   Plants affect their neighbors and the soil so we should try to place compatible or non-competitive plants near each other when possible.  A similar principle applies when deciding which plant follows recently removed ones (that’s called plant succession).  We don’t want to re-plant the same plant or one that needs the same soil nutrients in the same place over and over; that would risk depleting the soil and depriving the subsequent plants of nutrients that it needs to be healthy. Also, our second topic is succession planting – a great way to get more out of limited garden space and have your garden favorites available all summer and into the fall.

Here is a list of some common garden plants and recommended companions.  This doesn’t mean they are required neighbors, but we do know they are compatible, and they might even benefit from each other by repelling pests or sharing nutrients.

                                    Companions                                                 Incompatible

• Green Beans:           anything (beans add Nitrogen to the soil)           Onions
• Broccoli*:                   Beets, Onions, Spinach                                        Tomato, Dill
• Brussel sprouts*:      Beets, Onions, Spinach                                         Tomato, Dill
• Cabbage*:                 Beets, Onions, Spinach                                         Tomato, Dill
• Cauliflower*:             Beets, Onions, Spinach                                         Tomato, Dill
• Carrots:                      Peas, Lettuce, Tomato                                           Dill
• Corn:                          Beans, Peas, Squash, Cucumbers                      Tomato
• Cucumber:                Beans, Peas, Corn, Sunflowers                            Potato
• Eggplant:                   Beans, Marigold                                                    ~ none ~
• Lettuce:                      Carrots, Radish, Strawberry                                   ~ none ~
• Onion:                        Beets, Carrots, Lettuce, Cabbage* family           Beans, Peas
• Peas:                          Carrots, Radish, Cucumber, Corn, Beans           Onions
• Potatoes:                   Beans, Corn, Cabbage* family, Marigolds          Tomato, Squash
• Squashes:                 Corn, Beans, Nasturtium, Marigold                      Potatoes
• Tomato:                      Onion, Carrot, Nasturtium, Marigold                  Potatoes, Cabbages

You can also see from this list that the classic “Three Sisters” combination (pole beans, corn & winter squash) is made of 3 mutually beneficial plants that help each other with nutrients (beans add Nitrogen), weed suppression (squash leaves smother weeds), and support (corn stalks support the climbing beans).  It is an ingenious design that works!  There are more good details online here.

Succession planting simply means to repeat planting of the same crops over time to produce repeated harvests over time.  Successions are great way to maximize the productivity of limited garden space too.  For example, if you plant leaf lettuce or mesclun seeds every week you should harvest fresh salad greens every week all summer and into the fall.  I’ve found that a short row (4-6 ft. long) of different salad greens every week produces a good supply for fresh salads into November.  Late crops of carrots, turnips and beets can also follow (in the same place) after the harvests of early salad greens frees up some space. 

Bush beans planted every 2 weeks in June & July provide a good extension of harvests too. Too much zucchini is a common problem, but if you plant one hill of 3-4 plants now and another hill in early July that will spread the harvest out so it can be enjoyed over time. The same works for herbs such as dill and cilantro that tend to mature early before we can use them in pickles, salsas, and cooking. There’s some very good information and specific planting recommendation online here. 

My final suggestion is to grow a fall crop of broccoli and cauliflower because the cooler weather produces vigorous tender plants.  Since most garden centers don’t appreciate this secret, you probably will have to start your own seedlings.  I’ve found that July 1 is the date to plant those seeds to be ready for transplanting in early August.

What are your favorite companions or combinations to grow?  Please share your comments or questions in the space below.