If your tomatoes ripening too small they could be lacking water, nutrients, space for their root to grow or are being exposed to hot temperatures that are drying the soil. To slow the ripening process, keep the plant moist by watering it deeply and surround it with mulch.
Give plants lots of space to grow a healthy root system and plant them early in the spring season to allow the stems to develop strong before summer arrives.
This article will explore the top reasons why tomatoes ripen too small and 3 easy tips to grow larger fruit before they start to turn red.
6 Reasons why tomatoes ripening too small
Here are the top reasons why tomatoes ripen too small and how you can solve each one.
1. Shallow soil depth
Tomatoes grown in shallow raised garden beds can have their root system restricted which can limit the amount of nutrients and water the plant can absorb. This will lead to a smaller plant, smaller fruit and they will ripen before they get to full size.
When planting tomatoes in pots, choose a dwarf variety, plant them in pots that are at least 18 inches deep and wide and choose a top quality potting soil. Watering and fertilizing regularly is essential for tomatoes grown in pots.
They will be reliant on monthly feeds to keep them growing well. Start by fertilizing for the first 1 months with pelleted chicken manure and then switch to a tomato or fruit promoting fertilizer. Apply this in liquid form monthly to get the nutrients rapidly to the plant.
Fruit promoting fertilizer will deliver phosphorus to encourage more flowers and larger fruit as well as micronutrients such is iron and minerals such as calcium. This will get your tomatoes growing large, ripening later and avoiding nutrient deficiencies such as blossom end rot.
2. Poor soil
Tomatoes grown in the ground in poor soil can develop fruit that ripens fast. The plant will usually grow smaller with less developed stems which will develop smaller fruit that can ripen quickly.
Before planting your new tomatoes seedlings improve the soil with aged cow manure and compost. Mix it through to add lots of organic matter, to improve soil drainage and enable the plant to access the nutrients in the soil.
Heavy clay soils will be lightened with the addition of compost and aged cow manure and will help the roots to grow deeper and access water and nutrients from the deeper soil.
Sandy soils will benefit from this treatment as well. Organic matter will help the soil to hold water for longer and prevent the plant from drying out.
3. Drying out
Tomato plants that are allowed to dry out can quickly ripen their fruit as a response. I have found that my plants have developed stress symptoms after drying out, the fruit ripens fast and small and the leaves will droop.
Tomato plants need regular water to stop the fruit from ripening fast. The plant will sense the sign of stress and will divert water back to the center of the stem. The fruit will turn red fast as plant priorities reproduction.
Keep the plants well-watered and surround them with mulch. This will help to reduce the amount of water that evaporates from the soil and will keep the plant moist for longer.
4. Late summer planting
Tomatoes that are planted too late in the season will not establish at their maximum size and will develop smaller fruit that ripens faster. Planting tomatoes in spring after the frosts have passed is the best time to plant.
This will give the plant time to establish in the soil, grow large stems that will produce larger fruit. They will develop slower and ripen slower. This will give them the best chance to develop large fruit before they ripen.
5. Hot sunny summers
Tomatoes grown in very hot arid areas can develop small fruit that ripens fast. When I was growing tomatoes in a Mediterranean climate we would get summer temperatures above 108 Degrees Fahrenheit.
These days would cause all of the tomatoes to rapidly ripen no matter what size they were. If you live in a region that gets very hot summers, tomatoes will benefit from afternoon shade.
We made a small cover for our tomatoes where we could drape over 50% shadecloth to shade them in the afternoon. This would prevent the small tomatoes from ripening too fast and too small.
6. Too many tomatoes at the same time
Leaving too many tomatoes on the plant to develop at the same time will cause the plant to grow lots of smaller fruit rather than large ones. Indeterminant tomato varieties like Beefsteak and Grosse Lisse will develop larger tomatoes if excess flowers are removed. Leaving the plant to focus on 2-3 main bunches of tomatoes will give you larger fruit that ripens slower.
Top Tips to Grow Larger Tomatoes Before they Ripen
Growing tomatoes larger before they start to turn red is possible with a few easy tips. Check out my easy hacks for larger tomatoes before they ripen.
1. Plant them in good quality soil in the ground
Growing tomatoes in good quality soil in the ground soil will give you large, healthy tomato plants and large fruit. Tomatoes grown in the ground soil can reach their roots down deeper to support a larger plant.
Provide these large plants with a strong stake to support the stem and the fruit. You can train indeterminant or vine tomatoes to grow up and continue to produce fruit along the vine.
2. Regular fertilizer
Regular fertilizer is essential for good tomato growth and to prevent any deficiencies that can cause the fruit to ripen too early.
Using a tomato or fruit promoting fertilizer around 1-2 months after planting your seedling or when the flowers appear will give the plant the nutrients it needs. It will have a lower NPK ratio focusing on phosphorus for good flower and fruit development.
3. Water regularly
Providing your tomato plant with regular water will slow the rate of the fruit ripening. Plant that are under water stress will ripen their fruit fast to reproduce. Keep water in the soil for longer by mulching the plants with 2-3 inches of straw or sugar cane mulch.
Deep water your tomato plant at night or in the morning before a hot summer day. Check the soil and deep water with your hose or dripper system when the soil is dry 2 inches below the surface.
Check out this video for some huge heirloom tomato varieties.
My Tomatoes are Ripening Too Small | Summary
Tomatoes that are ripening too small are often caused by a lack of water, nutrients and poor soil. Growing tomatoes in the ground will usually give you the biggest tomatoes possible. Provide them with shade if you get hot summer afternoons to slow down the ripening process.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.