Is Grow a Paper Garden free?

Yes. It runs in your browser on phones, tablets and computers, with no download and no account.

Why do plants grow toward the light?

A hormone called auxin collects on the shaded side of the stem and makes those cells grow longer, so the stem bends toward the light. This is called phototropism.

Do sunflowers really follow the sun?

Young sunflowers do: their heads track the sun from east to west during the day and turn back east at night. Mature, blooming sunflowers stop moving and face east.

Can you overwater a plant?

Yes. Waterlogged soil has no air in it, so the roots cannot get the oxygen they need. The leaves turn yellow and the plant stops growing, just like in the game.

What is field capacity?

The amount of water soil holds after the extra has drained away under gravity, roughly 30% by volume for a loam. Plants use the water between field capacity and the wilting point, about 12%.

Grow a Paper Garden

Water the soil, drag the sun, and wake up the sleepy buds. Back to the game

How to play

Each garden gives you a window box, a few seed packets and a number of days. Pick a seed in the bar (daisy, tulip, bean or sunflower), then tap a patch of soil to plant it. Hold the watering can to tip it and pour, and drag it while you hold to water along the row. The front of the box is cut away, so you can watch the water soak down through the soil and see the roots grow. Darker soil is wetter soil.

Plants grow only in daylight, and only when their roots have the right amount of water. Too dry and they droop and sulk; too wet and they turn yellow and queasy. Drag the sun across the sky to see every stem bend toward it. Buds have tiny sleepy faces, and they wake up and smile when they bloom. Open flowers bring bees and, with luck, a butterfly. Bloom the flowers each garden asks for before the last sunset to earn up to three stars, then try the next garden. Finish them all to unlock a free garden with no clock.

Changed your mind about a plant? Tap the soil underneath it to dig it up and sow the selected seed instead. Tap a plant itself to tickle it.

Keyboard: arrow keys move the watering can, hold Space to pour, 1 to 4 pick a seed, P plants under the can, Q and E move the sun, and F toggles double speed.

Why plants lean toward the sun

A stem bends toward light because of a plant hormone called auxin. When light falls on one side of a shoot, auxin moves to the shaded side, and the cells there stretch faster, so the stem curves toward the light. This is phototropism, and Charles Darwin and his son Francis first showed in 1880 that the tip of a grass seedling senses the light. In the game every growing stem slowly turns toward wherever you put the sun, and a tall plant between the sun and a small one casts shade that slows it down.

Young sunflowers go further. Their heads follow the sun from east to west during the day and swing back to face east during the night, ready for sunrise. A study by Atamian and colleagues (Science, 2016) showed that the plant's internal clock drives this: the east side of the stem grows by day and the west side by night. Once a sunflower blooms it stops and faces east, which warms the flower in the morning and attracted about five times more bees in their experiments. The game's sunflowers do the same, with east on the left because you are looking south.

How plants drink

Roots take up water, which rises through thin tubes called xylem to the leaves, where about 97% of it evaporates through tiny pores. This transpiration pulls the water column up behind it. Only a small share is used in photosynthesis: 6 CO₂ + 6 H₂O + light → C₆H₁₂O₆ + 6 O₂. When the soil dries, the cells lose their water pressure (turgor) and the plant wilts.

The soil in the box is modelled as a loam. Water you pour soaks into the surface; anything above the soil's field capacity (about 30% water by volume) drains downward under gravity, and the box drips from its drainage holes. Below the wilting point (about 12%) the water is held too tightly for roots to pull out. Pour faster than the soil can soak it up and a puddle forms. Keep the roots waterlogged and the air spaces fill with water, the roots run short of oxygen, and the leaves yellow. Sunshine dries the top of the soil, so a hot noon sun means more watering.

Tips

Water a little and often. Watch the soil reading in the corner: "just right" is what the roots want.
Sunflowers are thirsty and slow; plant them first. Daisies are quick and forgiving.
Keep tall plants from shading short ones by moving the sun, or by planting the tall ones at the west end.
Bees count as visitors, and visitors add to your garden score.

Love living things? Watch a colony find food in ../follow-the-ants/ or grow ice crystals in ../grow-a-snowflake/.

Questions people ask

Is Grow a Paper Garden free?: Yes. It runs in your browser on phones, tablets and computers, with no download and no account.
Why do plants grow toward the light?: A hormone called auxin collects on the shaded side of the stem and makes those cells grow longer, so the stem bends toward the light. This is called phototropism.
Do sunflowers really follow the sun?: Young sunflowers do: their heads track the sun from east to west during the day and turn back east at night. Mature, blooming sunflowers stop moving and face east.
Can you overwater a plant?: Yes. Waterlogged soil has no air in it, so the roots cannot get the oxygen they need. The leaves turn yellow and the plant stops growing, just like in the game.
What is field capacity?: The amount of water soil holds after the extra has drained away under gravity, roughly 30% by volume for a loam. Plants use the water between field capacity and the wilting point, about 12%.