Ian Wilson
About Author
August 3, 2022

5 Tips for Late Season Tomato Care

Here are 5 tips to maximize the quantity and quality of your tomato harvest:

Fertilize as needed during flowering and early fruit set

Tomatoes are heavy feeders and may require more fertilizing than many other vegetables that aren’t in the ground for so long.  If you see any signs of low fertility, especially stunted growth or yellowing leaves, apply an all purpose organic fertilizer and water thoroughly into the root zone.  Fertilizer is best applied during flower set and early fruiting and will be less effective once you have begun harvesting tomatoes.

Reduce irrigation to your tomatoes once fruits begin to ripen

Tomatoes are extremely deep rooted and are very efficient and scavenging water lower in the soil.  Mature tomatoes (as long as their containers are large enough) will benefit greatly from reducing the frequency and volume of watering by as much as 50% once fruits begin to ripen.  This reduction serves two purposes.  First it induces a mild stress response in the plant encouraging it to put less energy into vegetation (leafy green growth) and more energy into making flowers and ripening the fruit that it has already developed.  Second, it concentrates the sugars and flavors in the ripening fruits leading to much more tomatoes!  This is the single most important late season tip for growing the most flavorful tomatoes!  As long as you don’t see signs of wilting or water stress, you are on the right track!

Reducing irrigation to your tomato plants in late Summer concentrates flavors and sugars in your fruit and leads to a superior harvest       Photo Credit: Shawn Linehan

Avoid overhead watering to prevent fungal disease

Tomatoes are very prone to certain fungal diseases, and minimizing water contact with the leaves is extremely important in preventing these diseases!  If possible, use drip irrigation instead of overhead irrigation.  And if you are watering by hand be very careful to avoid getting water on the leaves.  Watering in the morning instead of the evening can also be very helpful in allowing most of the moisture to be taken up by the plants during the day and minimize evaporation and humidity during cooler night time temperatures when fungal diseases are more likely to spread.

Continue to prune for air flow and sunlight

Proper pruning does two essential things:  It allows appropriate air flow within and between your plants to prevent infection and spread of harmful fungal diseases, and it allows sunlight to penetrate the canopy and ripen your fruits!  Prune out any leaves or branches that are hanging down and making contact with the soil.  Also prune out any branches that have escaped their cage or support.  If you were late in planting, or if your tomatoes are slow to fruit, head back the tallest branches on the plant.  These cuts will induce a stress response and hasten the ripening of immature fruits.

Taking steps to prevent fungal disease in your tomato plants will ensure an abundant harvest.  Proper air flow, plant spacing, appropriate irrigation, and proactive organic spraying will all help minimize the risk of fungal infection.

Proactively spray an organic fungicide to prevent fungal disease

Spraying an organic listed anti-fungal like Actinovate or Bonide Copper Fungicide can help prevent infection by Late Blight, which can be crippling to tomatoes.  Once Late Blight infects a tomato plant, it can be nearly impossible to eradicate, so preventive spraying is the best approach.  Proper plant spacing, air flow, and appropriate irrigation are still the most effective preventive measures, but proactive spraying can help too!

*Caution:  Even organic listed fungal sprays can be irritants and should be used only as explicitly directed.

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