Growing tomato plants from seed is a fun and rewarding way to get fresh, homegrown tomatoes While it does require some extra time and care compared to buying transplants, you’ll get the satisfaction of nurturing your plants from the very beginning. One of the keys to getting your seedlings off to a strong start is watering them correctly Underwatering can stunt growth, while overwatering invites fungal diseases. Follow these tips to keep your seedling’s soil moist but not soaked.
When to Start Watering After Planting Seeds
Once you plant your tomato seeds in seed starting mix or potting soil, the seeds need consistent moisture to germinate and begin growing. This means you should water the soil as soon as you plant the seeds. Gently water until the soil is thoroughly moistened but not dripping wet.
Check the soil daily by inserting your finger into the top inch. If it feels dry, add some more water. You want to keep it evenly moist, but not saturated. As soon as you see sprouts emerge in about 5-10 days, you can cut back to watering only when the top inch becomes dry.
How Often to Water Seedlings
How frequently you need to water depends on factors like temperature, humidity, air circulation, and sunlight exposure. In general, tomato seedlings need watering about every 2-4 days to keep moist but not wet. The warmer and drier your indoor growing area, the more often you’ll need to hydrate.
Stick your finger into the soil to gauge moisture before watering. If the top inch is dry, it’s time to water. If only the surface is dry but it’s still moist below, hold off until the next day and check again. Wait until the full top inch dries out for the next watering.
What is the Best Way to Water Seedlings?
It’s important to water the soil directly and avoid getting water on the seedling leaves. Wet foliage can lead to damping off disease. Use a watering can with a narrow spout to target the base of the seedling. Or set pots in a tray and add water to the tray, allowing it to wick moisture up into the containers from below.
Water gently to avoid dislodging seeds and small seedlings. Pour until water drains freely from the bottom drainage holes then stop. You don’t want water to collect and puddle in the saucer or tray under the containers.
How Much Water Do Seedlings Need?
Seedlings don’t need large quantities of water at a time, just frequent small drinks. About 1-2 ounces (30-60 mL) of water per individual seedling cell every 2-4 days is sufficient in most cases. This keeps the soil evenly moist but not saturated.
For larger seedling pots or flats, give about 1 cup (240 mL) of water across the entire flat or pot every 2-4 days. Focus on moistening the soil, not flooding it. Proper drainage is key to prevent waterlogged soil.
Signs Seedlings Need More Water
Check seedlings daily for signs they need a drink:
- Soil is dry when you stick your finger in the top inch
- Leaves are drooping or wilting
- Leaves are curling inward
Don’t let plants get overly droopy or wilty between watering. Seedlings that go too long without water may stop growing or even die.
Signs Seedlings Are Overwatered
It’s also important not to overdo watering. Signs of overwatering include:
- Standing water in saucers or trays
- Soil that stays soggy for several days after watering
- Soft, mushy stems at soil level
- Mold or fungus on the soil surface
If this happens, back off on watering frequency and quantity. Consider repotting in fresh, dry seed starting mix if damping off occurs. Improve drainage and air circulation to help excess moisture evaporate.
When to Harden Off Seedlings
Once seedlings grow to have about 2 sets of true leaves, it’s time to start the hardening off process to get them ready for transplanting outdoors. Slowly introduce seedlings to outdoor conditions over 7-10 days.
At this stage, cut back on watering frequency and allow the soil to dry out a bit between waterings. This helps the plants adapt to less frequent watering when they move to the garden.
Watering After Transplanting Outdoors
When transplanting seedlings to the garden, water them immediately after planting. Give each new transplant about 1-2 cups of water at its base. Then water daily for the first week while plants establish roots in their new location.
After a week, you can begin to taper off watering if rain provides adequate moisture. Mature tomato plants need about 1-1.5 inches of water per week from rain or irrigation combined. Less frequent, deep watering is better than frequent shallow sprinkling. Mulch around plants to retain moisture and reduce watering needs.
Proper watering in the early weeks helps your homegrown seedlings grow into thriving tomato plants. Pay close attention and tweak your watering routine based on your unique growing conditions. With a little care, your seedlings will be pumping out ripe, juicy tomatoes in no time!
Tips for watering tomato seedlings
This post should be called “It’s Hard to Be a Tomato Seedling” or “Kind Ways to Kill Your Seedlings!”
It just stuck its head out of the ground and found that it’s dark, cold, and there are still a few months until the weather is nice enough that there won’t be any frost at night!
If you put a tomato seedling in a dish of cold water with wet soil, it will die. This is especially true at night when the temperature drops. Too much water can make it hard for roots to grow because it takes away the soil’s air.
Also, seed compost can get hard, like a lump of mud, if it gets a lot of water from above.
Even worse, giving tomato food to a seedling will hurt its delicate roots (tomato food should only be given to established plants that are fruiting). After a couple of weeks, the seedling gets a fungal disease and looks like it’s going to die or is very sick.
But the book says: “tomato plants need plenty of water and are hungry feeders!”
Tomato plants need more food and water as they age, but not when they’re young. Lots of leaves and fruit on a tomato plant means it needs a lot of water. This is especially true if it is grown in a hanging basket when it is very hot outside. When plants are older they also need feeding regularly, especially if grown in containers where resources are limited.
On a scale of ten, though, a seedling needs one out of ten and a fruiting plant needs ten out of ten. This is true for both food and water.
When you plant seedlings, keep the soil just a little damp and don’t feed them. The food in the seed and potting compost is enough to get them through their first move to a single pot. You could also use multi-purpose compost or something similar.
Liquid seaweed extract is sometimes used on seedlings to encourage growth, but it is not essential.
If seedlings wilt give them a spray/mist with water – it’s the quickest way to revive them.
It’s so easy to kill plants with kindness – a bit like over-feeding tropical fish!
When and How to Water Your Tomato Seedlings
FAQ
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