When to Plant Tomatoes in PA

Tomato seedlings sprouting

Growing tomatoes can be a great endeavor that provides you with literal fruits for your labor! 

If tomatoes are started at the right time in Pennsylvania, they can produce fruit for a full season. Here’s some information for determining when you should plan your tomatoes this spring.

When to plant tomatoes outside in PA

Depending on where you are located in PA, you’ll want to start planting your tomato plants sometime between late April into May.

Keep in mind that anytime that you are planting cold-sensitive plants outside before Mother’s Day holds some risk. For this reason, if you want to be safe, it’s going to be a better bet to plant tomato plants around Mother’s Day.

If you have a way to protect the plant from the cold or are planting them in a container that you can carry inside over colder nights, you can start tomato plants as early as early April.

At Homestead Gardens, we start our tomato plants towards the end of February in heated greenhouses.

The earlier you can safely start tomato plants, the longer their season will be and the earlier you’ll receive those delicious red tomatoes. For most growers, planting tomato plants in May is going to be the best option, which sets them up to receive their tomato harvest in August and into the fall (assuming the plants are properly taken care of).

Green tomatoes on the vine

Factors to consider

The question of when to plant your tomato plants and the expectations of harvest depend on a bunch of factors:

  • The variety of tomato plant
  • The size of the plant plug (the soil its roots are planted in)
  • The weather for the current year (while almanacs and history’s average can do a decent job of predicting weather patterns, most times you need to make decisions based on the current year’s local weather patterns).

When should tomato plugs be planted?

For larger pots of tomato plants that are more established, you can wait to plant them outside or into a planter or container. With more space for their roots to grow and establish, you won’t be delaying the harvest of tomatoes by playing it safe and keeping the plants in the pots.

For smaller packs (think 4 pack or 3 packs) of tomato plants, consider waiting until the threat of a late frost is gone. A cold night could wipe out seedlings or small, unestablished tomato plants, so its important to be extra careful with them. 

While you’re waiting, you can transplant the small tomato plants into a larger container. This will help avoid the plant getting “root bound”, which is what happens when a plant’s roots run out of the soil in its pack and grow into each other to form a tightly intertwined root cube. Ultimately, this creates a plant that is not as healthy. If this ever happens, the best solution is to gently rip apart the roots a little before transplanting the plant.

When should tomato seeds be planted in PA?

If you are starting your tomato plants from seed, a good time to plant these seeds in PA is early to late February.

Make sure to have a good place to grow these seeds inside. The key will be to give the plants as much light as possible early on. If you have grower lights you can use those. Or, if you have a window that you can set the planted seeds next to, that works too.

Red tomatoes on a vine in PA

PA growing zones

Determining when to plant tomatoes in PA depends largely on the growing zones that you are in. 

What are growing zones?

Growing zones are mapped out areas that the USDA has identified as having a similar “hardiness” level. Each zone has a different level of weather exposure and extreme temperatures, so it’s important to follow local guidelines for each zone. PA’s zones include 5a, 5b, 6a, 6b, 7a and a very small section of 7b. 

Where you are in the state

It’s important to consider where you are in the state so that you can understand when to plant your tomato plants outside. 

If you are in Northwest PA, you’ll likely be dealing with harsher weather patterns from Lake Erie. If you are more southwest, you may be able to plant your tomato plants out a little earlier.

Weather conditions

Conditions are going to vary by year, so make sure you are keeping an eye out for the upcoming week’s weather before you plant your tomato plants outside.

Time frame

Tomato plants can be planted any time of day. Just make sure that they are given plenty of water early on and the necessary fertilizer.

If you notice their leaves are turning yellow a few weeks after planting your tomato plants, it may be time to give them some fertilizer.

Tomato plants on the vine

Conclusion

While May is a good time to plant your tomato plants in PA, your garden as a whole will have varying times that it will be best to plant items.

For example, some vegetable plants cannot handle the PA heat very well through the summer. Spinach, arugula, lettuces, and herbs can all be more difficult to grow in the heat of the summer, but are great for an early spring harvest or fall harvest.

Other vegetables are best planted early (after the last frost) and can bear vegetables all summer long into the fall. As long as a tomato plant is properly maintained, this can be the reality for your garden.