Tomatillos are the tangy, husked cousins of tomatoes most often found in salsa verde. These tropical Mexican fruits thrive in the same sunny, warm conditions as tomato crops.
When growing tomatillos in your garden, it is vital to plant them in an area with well-drained rich soil and plenty of sun exposure.
But how much sunlight do tomatillos really need? Can they survive in partial shade? Let’s dig into everything you need to know about the light requirements for growing tomatillos, plus a few signs that your plants may not be getting enough sunshine.
The Quick Answer
Tomatillos need at least 6 to 8 hours of sunlight daily during the growing season. When tomatillos don’t get enough light, they may not produce fruit. Partially shaded tomatillo plants often appear stunted, weak, lanky, and pale.
The strongest, highest-yielding tomatillo plants demand full sun and an unshaded, south-facing garden area. Tomatillos must not get shaded out from nearby shrubs, trees, or structures.
Before planting, ensure that your tomatillo beds will not fall under morning or afternoon shadows cast by your home. Young seedlings or indoor potted tomatillos often require supplemental lighting like LED grow lights to ensure they don’t get “leggy.”
The Detailed Answer
Full sun is preferred for optimal fruit production.
Tomatillo plants need at least 6 hours of direct sunlight daily to support healthy growth. Without enough light, you may not get any husked salsa verde fruits at all! It is especially important for gardeners in northern climates to plant tomatillos in full sun.
Southern growers can get away with a bit more shade during the hottest summer months. While tomatillos may tolerate partial shade, they won’t thrive in it. Pale yellowing leaves, stunted growth, lanky stems, and lack of fruit production are all symptoms of insufficient light.
As a native plant of Mexico, it should be no surprise that tomatillos prefer hot, sunny climates. These husked fruits are members of the sun-loving Solanaceae family, which also includes peppers, potatoes, eggplants, and tomatoes.
The Latin root sol means “sun”, which explains why the Solanaceae family loves to soak up those vibrant, golden rays.
Physalis longifolia (longleaf ground cherry or wild tomatillo) is a wild ancestor of our modern garden tomatillos. It can be found spreading through dry fields, open pastures, and wild meadows. It even grows in roadside ditches.
This wild (but toxic) nightshade is so vigorous in hot, sunny, disturbed areas that it is considered a noxious weed in California! Although garden tomatillo varieties are far more well-behaved and are often planted in salsa gardens, they still have that drive to soak up as much sunshine as possible.
Where Tomatillos Grow Best
These popular vegetables grow best in bright sunlight with nutrient-rich soil.
Tomatillos produce the greatest yields when grown in bright direct sunlight and rich soil. They are perennial in zones 10 and 11. They can also thrive as annuals in USDA hardiness zones 5 through 9.
Northern gardeners need to pay more attention to the solar aspect (direction of the sun) throughout the growing season. The Google Earth Pro app can be a useful tool for following the sun’s shadow over your home and garden during different parts of the year.
But old-timers would prefer to sit on the porch and observe quietly. Either way, remember that morning and evening shade over your tomatillos can cut into those vital 6 hours they need for adequate growth.
In temperate climates, you should plant tomatillos in the late spring or early summer once all risk of frost has passed and the sun shines higher in the sky.
During chilly spring weather, the plants may require cold protection (like a row cover or low tunnel). But you don’t want this additional heat insulation to compromise the plants’ sun exposure. Use a thin, lightweight row cover or polyethylene plastic to ensure the highest light transmission into a tunnel.
Growing in Partial Shade
While tomatillos can grow in partial shade, they truly prefer full sun conditions.
Tomatillos will tolerate partial shade, but their growth will be slower. Compared to plants grown in full sun, shaded tomatillos may not flower and fruit as abundantly.
In extremely low-light conditions, tomatillo plants will not produce any fruits because their photosynthesis is hindered, and the plant cannot support fruit development.
If the sunniest portions of your garden are already occupied, you can plant tomatillos in an open area that receives some morning or afternoon shade. Southern growers with extremely hot summers will have the best luck with shaded tomatillos.
Northern growers are encouraged to prune back nearby shrubs or trees that block your garden’s sunlight. Building a trellis and planting indeterminate varieties can help encourage the plants to vine upward for more light exposure.
Signs Your Tomatillo Needs More Sunlight
Yellowing leaves and slowed fruit production are signs your plants need more sun.
Whether you’re growing tomatillos indoors, in patio containers, or out in the garden, they will clearly tell you when they are not getting enough light. The most common symptoms of insufficient sunlight include:
|Pale or Yellow Leaves||Sunlight is the key ingredient for photosynthesis. When a plant doesn’t get enough light to its chloroplasts, it produces less chlorophyll (the pigment that makes leaves green), which causes the leaves to turn pale, yellow, or even white.|
|Slow or Stunted Growth||Because of the reduced photosynthesis in the plant’s leaves, tomatillos in low light will not be able to grow very fast. After all, sunlight fuels photosynthesis, which is how the plant creates the food it needs for growth. Your plant may look stunted, weak, and small.|
|Lanky Stems||Have you ever seen a houseplant arching toward a window? In an effort to reach more light, tomatillo plants will do the same thing. As they reach for more sun, tomatillo plants will lengthen their stems. As a result, the plant can appear lanky and weak.|
|Fewer Flowers||The compounding effects of the above conditions ultimately result in little to no flower production. Tomatillos without enough light will not flower, or their flowers will be very small. They are stuck in survival mode and don’t have enough sugars to fuel reproduction. A lack of flowers can also be caused by extreme heat or cold.|
|Lack of Fruit||Without many flowers, there won’t be much fruit! Shaded tomatillos yield significantly less than their sun-grown counterparts. Sometimes they will develop empty husks that never mature into full-size juicy tomatillos. Low pollination, low fertility, and plant disease can also contribute to a lack of fruit production.|
Tomatillos are vigorous, lush plants that can grow 4 feet or taller! If your plants are not reaching their greatest potential, it is probably because they aren’t getting enough sun, drainage, or fertility. They could also be facing problems with water, pests, or disease. Potential causes of poor tomatillo growth include:
- Insufficient sunlight: Tomatillos need 6 to 8 hours of direct sunlight every day.
- Poor drainage: Like tomatoes, tomatillos need well-drained soil. They do not grow well in heavy clay or waterlogged soils, which leads to root rot and other diseases.
- Low fertility: Tomatillos require moderately rich soil. It helps to amend generously with compost and provide a nice dose of all-purpose fertilizer when planting.
- Overwatering: Tomatillos don’t like soggy, “wet feet” in their root zone. Too much water can cause yellow leaves, root rot, and stunted growth.
- Not enough water: Tomatillos are fairly drought tolerant, but they aren’t invincible. Tomatillos need about an inch of water every week. A lack of irrigation can cause undersized plants and fruits. This is doubly true during fruit development; inconsistent watering (particularly of the “feast or famine” variety) can cause cracked or damaged fruit or can cause smaller fruit. Try to maintain consistency in your watering so the plant doesn’t have to deal with sudden shifts in moisture level.
- Pests and disease: If your tomatillo leaves have holes, yellow leaves, brown or black spots, or significant amounts of missing foliage, there may be an insect or fungal culprit at work. Keep an eye out for leaf spotting, various types of caterpillars that normally go after other solanaceous plants, or small sucking pests like aphids or thrips.
You can avoid many tomatillo troubles by planting these delicious fruits in a bright, sunny location. However, if you’ve established that your tomatillo plants aren’t getting enough sun, the quickest way to save them is to transplant them to a brighter location.
This process is super simple, and the plants typically bounce back within a week or two! The plants recover more quickly when they are young. To save your shaded tomatillos:
- Use a shovel or trowel to lift the plant from the soil gently.
- Dig at least 6” from the plant base to avoid root damage.
- Place the plant in a pot or newspaper wrap to protect the roots.
- Check that the new area has plenty of light and well-drained soil.
- Amend with compost as needed.
- Tuck the tomatillo plant into the soil.
- Cover it with a lightweight layer of row cover.
- Secure with rocks or landscape staples.
- Keep the cover on for a few days to help the plant adjust.
- Don’t panic if a few leaves appear sunburnt.
- Keep the soil moist but never soggy.
- Do not leave the cover on for more than a week.
If you can’t move your tomatillos, try trimming back nearby large plants casting shadows over the bed. If you’re growing in containers, invest in an LED grow light and hang it 12