This is a weekly feature in which garden authority Gayla Trail, the creator of YouGrowGirl.com answers frequently asked questions and offers gardening advice.
I'm new at growing tomatoes. I’m happy to report that my first plants are huge and lush but they aren’t producing any flowers or tomatoes. Is this normal?
I know this problem well and I also remember how confusing it was when I first started growing tomatoes. After all, lush plants should be the goal, am I right?
A few things could be going on here so I’m going to provide a little background first and then get to what I think the issue is.
Tomatoes are incredibly diverse, which can make them a bit of a struggle to understand, but also incredibly fascinating plants to grow. Normal for a tomato depends on the type, the specific variety and your climate. There are several different types of tomatoes, but the main two are determinates, that grow into bushes and then produce all of their fruit at once, and indeterminates that grow into tall vines and produce continuously until the frost kills them. Many determinates tend to produce fruit towards the early end of the season. Indeterminates tend to be slower as they need to gain size before fruiting. There are early varieties; however, most need at least a month in the ground (from transplant), if not longer, before the first blossoms appear. For this reason it’s always helpful to know both the type and the variety you are growing so you know how to grow your plant and when to expect blossoms and fruit. My advice:
Too Much of a Good Thing
You don’t say which type you are growing but because you describe them as “huge,” I’ll hazard a guess and say indeterminate. There’s a chance that you are growing a slower variety and perhaps blossoms will appear shortly without any intervention. However, you used the word “lush” to describe the plants, and go on to say that they haven’t produced flowers at all yet—these are all tell-tale signs of an overindulgence in fertilizer, specifically when it is high in nitrogen.
Nitrogen is the nutrient most responsible for growing lush, vibrant leaves and stems. Tomato plants, especially the really big indeterminate vines need it most when they are young so that they can reach their full potential. Unfortunately, too much nitrogen keeps the plants contented without the pressure to reproduce. As long as you continue hooking them up with their fix, greedy tomatoes will reward you with lush and lovely leaves, but nary a fruit shall form. And we want fruit!
A little tough love will give your plants the jolt they need to start the reproductive portion of their life cycle. To begin, stop giving them nitrogen-rich fertilizers cold turkey, including compost and manure. If you’re not sure, check the nutritional analysis provided on the product package. You should see a set of three letters (N-P-K) or three numbers in their place, which stands for Nitrogen, Phosphorus and Potassium. It’s okay to continue feeding with a commercially prepared mix as long as the nitrogen number is much lower than the other two. Better still, continue feeding with a potassium-rich fertilizer such as sea kelp. You can also help blossoms stay around when they do appear by spraying them directly with a diluted mixture of Epsom salt and water; about 1 teaspoon to 1 quart of water.
Next, do away with some of that thick, lush foliage. Start by removing the lower leaves to reveal a main stem, but keep the top growth to provide sun protection for future fruit. Not only will it provide good airflow and help to prevent disease, but I also believe that this sort of treatment jump-starts the urge to reproduce. You’ll also want to remove suckers: new growth that comes up between branches. Don’t use this method with determinate (bushing) types. They are much smaller plants that need the bushy growth to support fruit production. Cutting back on nitrogen should be enough to get them rocking and rolling and a big, gorgeous pile of fruit coming your way in no time!