What to Do With Tomato Plants in June – 5 Early-Summer Jobs for a Bigger, Juicier Harvest
It's time to tie in stems, remove side shoots, and start fertilizing your tomatoes
Now that June is here, my tomato seedlings are shooting up and getting ready for another productive season. But, to ensure an abundant harvest in the coming months, there are a few tasks to tick off now.
Growing tomatoes is joyous, as they're one of the most beginner-friendly veg to grow. However, without doing some essential care along the way, you could accidentally make some common tomato growing mistakes. In June, key tasks include tying in vines, removing side shoots, and starting to feed your plants as bright yellow flowers emerge. Of course, your climate and when you sowed your seeds will impact exactly what needs to be done now, though all of these tomato growing tasks shouldn't be far away.
So, to help keep your tomatoes in top form, I asked a gardening expert what to do with tomato plants in June. Here are five key tasks they pulled out.
1. Support Vining Varieties
This task all depends on whether you're growing indeterminate or determinate tomatoes, i.e. vining or bush types. The former will need staking as the plants grow bigger and create vines that need a support to climb.
If you already transplanted your tomato seedlings, you likely have a plant support in place (like these bamboo stakes from Amazon or this tomato cage from Walmart). This provides a structure for the vines to climb, so keep in mind how tall your specific variety typically grows when selecting a support.
Once seedlings are around 10-12 inches in height, you should gently tie them to the support to hold them upright and train them.
'Use soft materials that won’t damage the stem, such as special plastic clips, garden tape, or strips of cotton fabric,' says Halina Shamshur, gardening expert from Plantum.
'Never use thin fishing line or wire, and don’t tighten the ties too much. You need to leave some space for the stem to thicken as the plant grows,' she explains.
Popular choices are soft ties and garden twine (like this from Lowe's).
As the main stem continues to grow, tie it in to prevent flopping. You can also use the tomato string method to train indeterminate varieties – a method that provides plenty of airflow.
Halina Shamshur is a resident plant expert for the Plantum app, which helps users identify plant species, diagnose their conditions, and get specific care advice. Halina has over 25 years of experience as a professional botanist and five years of experience consulting on botany-related topics for Plantum.
2. Remove Side Shoots
As tomato stems grow, it's important to check them regularly for side shoots, or 'suckers.' These are found between the main stem and the branching stems, emerging as smaller offshoots.
The reason you should prune your tomato plant to remove them is because they drain the plant's energy with unnecessary vegetative growth.
You can use your fingertips to pinch them off, redirecting the plant's energy towards flower production and then eventually fruiting.
'Also, remove the lower leaves that touch the soil to prevent fungal diseases,' Halina says.
There are several tomato plant diseases to watch out for, but removing the lowest leaves improves air circulation and prevents soil-borne diseases from touching the foliage.
Later on, this also helps redirect the plant's energy into fruit production by removing unproductive lower foliage.
Always use clean and sharp pruning tools for this, like these Fiskars gardening snips from Amazon.
'Cut off no more than 1–2 leaves per week to avoid stressing the plant,' Halina advises.
3. Feed Your Tomato Plants
Fertilizing tomatoes is a necessity if you want to increase your tomato yields, as these crops are heavy feeders. But, they only need to be fertilized once the yellow flowers appear.
'At the beginning of flowering and fruit formation, use fertilizers high in potassium and phosphorus. Don’t apply nitrogen fertilizers, as this will cause the plant to produce excessive foliage at the expense of fruit,' Halina advises.
Plant fertilizer numbers indicate the volume of each essential plant nutrient in the product. As tomatoes begin forming flowers, you should use a tomato fertilizer with a low nitrogen number (like this from Amazon) to support cropping rather than vegetative growth.
You should apply tomato feeds (this one from Lowe's is also a good option) once a week during the flowering stage to support production. Take care not to overfeed, as it can burn roots and lead to flowers dropping.
4. Water Consistently
As temperatures rise in early summer, it's really important to keep on top of watering tomato plants so they stay hydrated. Too little water during hotter spells can result in tomato plants wilting.
'Water your tomatoes regularly and don’t allow the soil to dry out. It should remain moist but not waterlogged. If it dries out, tomatoes will drop buds,' Halina warns.
'In sunny, hot, and dry weather, the plants may require daily watering. At moderate temperatures, water approximately every 2–3 days. Don’t water from above or wet the leaves, pour only at the base of the plant. This helps prevent sunburn and reduces the risk of fungal diseases such as late blight,' she advises.
I always rely on my soil moisture meter (like this from Amazon) to identify whether my plants need watering. This helps prevent overwatering, so you don't put your tomato plants at risk of root rot or tomatoes splitting from excess water.
5. Protect From Scorching Temperatures
Even though tomato plants are sun-lovers, extreme hot weather does pose a risk. For this reason, you should keep an eye on the forecast in the summer months and protect plants from a heatwave accordingly.
'At high temperatures (above 90°F), tomato pollen becomes sterile, which leads to flowers dropping and fruit failing to form,' Halina warns. 'Bright sun exposure can also cause leaf burn,' she adds.
Generally speaking, the ideal temperature for tomato plants is between 64-80°F. Higher than this can cause symptoms like wilting and bud drop, resulting in less fruit.
For this reason, Halina suggests using things like a 50% shade cloth (like this one available on Amazon) to protect tomato plants.
You can also apply mulch to lock in moisture around the base of your tomato plants, helping them stay hydrated during hotter spells. This bark chip from Lowe's is a good choice, just take care to leave a 2-3 inch gap around the stems to prevent fungal diseases and rot.
And if you're growing your tomatoes in a greenhouse, don't forget to ventilate your greenhouse during extreme heat to avoid sweltering temperatures inside. This greenhouse thermometer from Walmart can help you monitor the growing conditions.
What to Shop
Mix this organic tomato feed with water to apply weekly during the flowering and fruiting stage.
This set of 6 tomato cages provides a support for vining tomatoes to climb. It has pointed edges to easily insert into the soil for a stability.
These gardening snips are ideal for pruning tomato plants. They have a non-stick micro-tip blade for precise cuts.
Watering is really key to get right over the next few months. Irregular watering can cause tomato splitting, blossom end rot, and wilting. Checking the soil moisture regularly is the best way to ensure your plants are sufficiently hydrated in warmer conditions.
You may also be interested in finding out more about tomato tapping during the flowering stage, which can bring bigger yields later on.
If you love inspiring garden ideas, outdoor advice, and the latest news, why not sign up for our newsletter and get the latest features delivered straight to your inbox?
