House Tomato - Care Sheet

Overview

House Tomato usually refers to the compact heirloom tomato cultivar ‘House’, grown for edible red fruit on a sunny windowsill. Its botanical name is Solanum lycopersicum; it is a true tomato, rather than an ornamental plant with tomato-like berries. Seed suppliers describe plants reaching approximately 60 cm / 24 in indoors, although size varies with growing conditions.

This guide assumes you have the named ‘House’ variety. Check the label, since other tomatoes sold for indoor growing can have different habits. Care is intermediate indoors: warmth is straightforward, but sufficient light, steady watering and flower pollination need attention. Healthy plants may survive several seasons under protection, although continuous winter harvests are not guaranteed.

Quick Facts

Light

Choose your sunniest window, preferably south-facing in the Northern Hemisphere. Aim for at least six hours of direct sun, with more generally supporting better cropping. Indoor glass, nearby buildings and winter days can substantially reduce usable light.

If stems stretch or flowering is weak, add a suitable grow light. A 12–16-hour lighting period is a useful starting point; follow the fixture’s distance guidance and provide darkness overnight. Introduce plants gradually to stronger sunlight.

Water

Keep the root zone consistently moist without leaving it saturated. Check the compost daily and water when the surface begins drying, before the root ball becomes dry. Water thoroughly until excess drains out, then empty the saucer. Large plants in hot windows may need daily watering; cool, dim conditions require less. Avoid alternating drought with heavy soaking, which encourages cracked fruit and blossom-end rot.

Humidity

Moderate humidity with gentle air movement suits tomatoes. Around 60–70% relative humidity is a greenhouse pollination target, rather than a strict household requirement. Avoid creating a damp enclosure to reach it. Persistent condensation and wet foliage encourage disease; ventilate without exposing plants to cold drafts. Routine leaf misting is unnecessary.

Temperature

Aim for daytime temperatures of 21–27°C / 70–81°F and slightly cooler nights around 17–19°C / 63–66°F. Keep plants frost-free and away from cold window glass. Excessive heat can interfere with pollination and fruit development, especially above approximately 30–32°C / 86–90°F. Ventilate sunny rooms and move plants away from radiators.

Soil & Potting

Use a quality peat-free container compost that holds moisture while draining freely. Avoid dense garden soil in pots. A container around 30 cm / 12 in across is a sensible starting choice for a mature compact tomato; larger pots make moisture easier to manage. Ensure drainage holes remain clear.

Plant sturdy young tomatoes slightly deeper than previously grown, keeping leaves above the compost. Add a small stake if fruit-laden stems need support.

Feeding

Allow for any fertilizer already included in fresh compost. During active growth, follow the product label for feeding container vegetables. Once the first fruits begin swelling, use a high-potassium tomato feed every 10–14 days, or at the manufacturer’s specified interval. Excess nitrogen encourages leafy growth at the expense of fruit. Reduce feeding when growth slows in poor winter light.

Repotting

Move seedlings into individual pots, then progressively larger containers as roots fill the available space. There is no fixed monthly repotting schedule. Roots crowding drainage holes or compost drying unusually quickly suggest more room is needed. For plants retained through winter, assess root space and compost condition in spring; refresh or repot before vigorous growth resumes.

Propagation

Sow seeds in seed compost and keep warm, approximately 20–25°C / 68–77°F, with even moisture. Provide strong light immediately after germination. Pot seedlings individually once they can be handled safely by a leaf.

Healthy stem cuttings offer another route. Take a non-flowering shoot approximately 10–15 cm / 4–6 in long, remove lower leaves and insert into moist propagation compost. Keep warm in bright, indirect light until rooted. Avoid propagating visibly diseased plants.

Common Problems

Flowers without fruit

Improve light and avoid temperature extremes. Tomato flowers are self-fertile, but indoor pollen transfer benefits from gently tapping open flower clusters. Excess nitrogen and moisture stress can also reduce cropping.

Dark patches beneath fruit

Blossom-end rot reflects inadequate calcium reaching developing fruit, often because watering fluctuates. Stabilize moisture and drainage first. Damaged tissue will not recover; calcium supplements are not automatically the solution.

Split fruit

Sudden water uptake after a dry spell can crack skins. Maintain consistent watering and harvest fully ripe fruit promptly.

Sticky leaves or small flying insects

Check leaf undersides for whitefly or aphids. Isolate affected plants and remove pests where practical. Use only treatments labeled for edible tomatoes and indoor use, observing harvest intervals.

Toxicity & Pet Safety

This plant is not pet-safe. Tomato plants are toxic to cats, dogs and horses, particularly their green parts and unripe fruit. ASPCA lists ripe fruit as non-toxic, but that does not make the whole plant safe. Toxicity varies across the wider nightshade family; never assume other ornamental Solanum berries are edible. Keep plants and prunings inaccessible, and contact a veterinarian if ingestion is suspected.

Seasonal Care

Spring and summer offer the easiest growing conditions. If moving outdoors, acclimatize gradually after frost risk passes. Before bringing plants inside in autumn, inspect carefully for pests. In winter, provide maximum light and reduce watering to match slower growth. Keeping a healthy plant alive is often more realistic than maintaining summer yields; restart from seed if an older plant declines.

Quick Tips

• Confirm that the label names the ‘House’ tomato variety.
• Give it your brightest growing position.
• Check compost moisture daily.
• Empty saucers after watering.
• Tap open flower clusters gently to aid pollination.
• Keep foliage and green fruit away from pets.