How to grow orchids in summer? - Plant Care Guide

To grow orchids in summer effectively, focus on adjusting watering frequency, increasing humidity, managing light intensity to prevent sunburn, and ensuring good air circulation. Summer heat and increased light levels demand more consistent attention to these core care elements to keep your orchids thriving.

How does summer heat affect orchids?

Summer heat significantly impacts orchids, often requiring adjustments to their care routine. While many orchids originate from warm, tropical regions, extreme or prolonged high temperatures can still stress them, especially when combined with other summer factors like intense sunlight and varying humidity.

1. Increased Transpiration and Water Loss: Higher temperatures cause orchids to transpire (lose water through their leaves) more rapidly. The potting medium also dries out much faster due to increased evaporation. This means orchids will need more frequent watering in summer compared to cooler months. If left unaddressed, the increased water loss can lead to dehydration, shriveled pseudobulbs, wrinkled leaves, and overall stress.

2. Risk of Sunburn: Alongside the heat, summer often brings more intense sunlight. While orchids need bright, indirect light, direct scorching sun can quickly lead to sunburn on their leaves. Sunburn appears as bleached, yellow, or black spots that are irreversible and can weaken the plant. The increased heat makes plants more vulnerable to sunburn, even if the light level wasn't problematic in cooler seasons.

3. Humidity Fluctuations: While many tropical orchids love humidity, summer can bring both periods of high humidity (like during thunderstorms) and very dry air (especially with air conditioning running indoors). Rapid changes or sustained low humidity combined with high heat can stress orchids, causing leaves to droop or pseudobulbs to shrivel.

4. Faster Potting Media Breakdown: The increased warmth and frequent watering accelerate the decomposition of organic potting media (like bark chips). As the medium breaks down, it loses its aeration properties, becoming compacted and holding too much moisture, which can lead to root rot.

5. Pest Proliferation: Warm, humid conditions can sometimes create an ideal environment for common orchid pests like spider mites, mealybugs, and scale insects to reproduce more rapidly. Stressed plants are also more susceptible to infestations.

6. Growth Cycle Impact: For many orchids, summer is an active growth period where they put out new leaves and roots. Proper care during this time is critical for the plant to store energy for future blooming. However, extreme heat can sometimes cause a temporary growth stall as the plant focuses on survival.

Understanding these effects of summer heat is the first step in adapting your care routine to grow orchids in summer successfully, preventing stress and preparing them for future blooms.

What watering adjustments are needed for orchids in summer?

Watering is one of the most critical adjustments you'll make to grow orchids in summer successfully. Due to increased temperatures, more intense light, and potentially lower indoor humidity (from air conditioning), orchids will use and lose water much faster.

1. Increase Frequency, Not Quantity: The most common mistake is to simply give orchids more water at each watering session. Instead, you need to water more often, while still ensuring thorough drainage.

   • From every 7-10 days to every 3-5 days: A common shift for many Phalaenopsis orchids. Terrestrial orchids like Paphiopedilums might need watering every 2-3 days.
   • Check the Potting Medium: Always rely on checking the potting medium, not a strict schedule. Stick your finger into the pot: if it feels dry about 1-2 inches down (or if bark feels crunchy), it's time to water. For clear pots, look for condensation to disappear or roots to turn silvery. A soil moisture meter designed for orchids can also be helpful.
   • Lift the Pot: Get used to the weight of a dry pot versus a wet one. Dry pots are surprisingly light.

2. Water Thoroughly Until Runoff: When you do water, ensure you saturate the entire potting medium.

   • How to water: Place the pot in a sink or basin. Pour room-temperature water through the potting mix until it drains freely from the bottom holes. Allow the pot to sit and drain completely for 10-15 minutes to avoid standing water. Some growers prefer to soak the pots for 15-30 minutes to ensure full rehydration, especially if the medium has become very dry.

3. Consider Watering in the Morning: Watering early in the day allows any excess moisture on leaves or crowns to evaporate before cooler evening temperatures set in. This significantly reduces the risk of fungal or bacterial rot, which thrives in damp, cool conditions.

4. Monitor Potting Medium Condition: Increased watering frequency can accelerate the breakdown of organic media like bark. As bark breaks down, it becomes more compacted and holds too much moisture, increasing the risk of root rot. If your medium looks degraded or soggy, summer might be a good time to consider repotting (if the orchid is not in bloom or actively growing a flower spike).

5. Adjust for Outdoor vs. Indoor Placement:

   • Outdoor Orchids: Will likely need even more frequent watering due to increased air movement and direct exposure to rain (or lack thereof). Check daily.
   • Indoor Orchids (with AC): Air conditioning can significantly dry out the air, leading to faster evaporation despite cooler ambient temperatures. This might paradoxically require more frequent watering than a non-AC indoor environment.

By diligently adjusting your watering routine and constantly monitoring your orchids' needs, you can keep them adequately hydrated and thriving throughout the summer months.

How should light be managed for orchids during summer?

Managing light is crucial to grow orchids in summer, as increased sunlight intensity can quickly lead to sunburn, while too little light can hinder growth and future blooming. The goal is to provide bright, indirect light.

1. Assess Light Intensity: Summer sun is much stronger than winter sun. What was ideal indirect light in winter might be scorching direct sun in summer.

   • Observe Your Orchids: Look for signs of stress. Yellowing or reddish tint on leaves can indicate too much light. Bleached, crispy, or black spots indicate sunburn.
   • "Hand Test": Place your hand about 6-12 inches above the leaves. If you feel warmth, the light is likely too intense.
   • Light Meter (optional): For precision, a light meter can help you measure actual foot-candles or lux, but visual cues are often sufficient.

2. Provide Adequate Shade:

   • Indoors:
     • Sheer Curtains: Use sheer curtains or blinds to diffuse direct sunlight coming through windows.
     • Relocate Plants: Move orchids further away from south or west-facing windows. North or east-facing windows are often ideal during summer as they receive less intense direct sun.
     • Consider a Different Room: If a particular room gets too much intense sun, move orchids to a brighter but more diffused location.
   • Outdoors:
     • Under Trees: Place orchids under the dappled shade of deciduous trees or larger shrubs.
     • Shade Cloth: Use shade cloth (typically 50-70% shade) to create a protective canopy for outdoor orchids.
     • Patio or Porch: A covered patio or porch that receives bright, indirect light is an excellent summer spot.

3. Rotate Plants Regularly: If your light source is directional, regularly rotating your orchid pots (e.g., once a week) ensures all sides of the plant receive even light exposure. This promotes balanced growth and prevents the plant from leaning excessively towards the light source.

4. Monitor Leaf Color: A healthy orchid leaf color is usually a medium-green.

   • Too Much Light: Leaves might turn pale green, yellowish, or develop a reddish/purple tinge.
   • Too Little Light: Leaves can become very dark green and floppy, and the plant may not produce new growth or blooms.

By carefully monitoring and adjusting the light exposure, you can protect your orchids from sunburn while still providing them with the energy they need to thrive and store resources for their next blooming cycle during the summer.

Why is humidity important for orchids in summer?

Humidity is critically important for orchids in summer because most popular orchid varieties are epiphytes, native to tropical environments where high atmospheric moisture is abundant. While watering addresses moisture in the potting medium, humidity addresses moisture in the air around the leaves and roots.

1. Combating Increased Transpiration: As discussed, summer heat causes orchids to transpire (lose water) more rapidly. Low humidity exacerbates this water loss. When the air is dry, water evaporates from the leaves more quickly, putting significant stress on the plant. Adequate humidity helps to slow down this rate of transpiration, allowing the plant to retain more internal moisture and reducing the risk of dehydration, shriveled pseudobulbs, and wrinkled leaves.

2. Mimicking Natural Habitat: Most orchids thrive in environments with 60-80% relative humidity. While indoor home humidity rarely reaches these levels, especially with air conditioning running (which dries the air), supplemental humidity helps to mimic their natural tropical habitat, making them feel more comfortable and promoting healthy growth.

3. Supporting Aerial Roots: Many orchids, especially Phalaenopsis, have aerial roots that extend outside the pot. These roots are adapted to absorb moisture directly from the air. In low humidity, these aerial roots can shrivel and die back, weakening the plant's overall ability to absorb water. High humidity helps keep these roots plump and active.

4. Preventing Pest Issues: While high humidity can sometimes encourage fungal issues if combined with poor air circulation, consistently low humidity can create an ideal environment for certain pests, particularly spider mites. These tiny pests thrive in dry conditions and can rapidly multiply, causing significant damage to orchid leaves. Adequate humidity helps deter them.

Ways to Increase Humidity for Orchids in Summer:

• Pebble Trays: Place orchid pots on trays filled with pebbles and water, ensuring the bottom of the pot doesn't sit directly in the water. As the water evaporates, it increases localized humidity around the plants.
• Humidifiers: A room humidifier is the most effective way to consistently raise ambient humidity, especially in dry indoor environments or where air conditioning is used.
• Grouping Plants: Grouping several orchids or other houseplants together can create a small microclimate with slightly higher humidity as plants transpire collectively.
• Misting (with caution): While misting leaves directly can provide a temporary boost, it's generally not recommended as a primary long-term solution. It can lead to water sitting in the crown or leaf axils, encouraging bacterial and fungal rot, especially without good air circulation. If you do mist, do it early in the morning so the water has time to evaporate before evening.

By actively addressing humidity needs, you provide a more stable and supportive environment for your orchids to grow in summer, minimizing stress and promoting robust health.

Should orchids be fertilized more in summer?

Yes, orchids typically benefit from more frequent fertilization in summer, as this is often their peak growing season. Increased light, warmth, and humidity (if managed correctly) provide the energy and conditions for rapid growth, and this growth demands more nutrients.

1. Active Growth Phase: For many popular orchid varieties, including Phalaenopsis, Cattleyas, and Oncidiums, summer is the period of active vegetative growth. This means they are putting out new leaves, pseudobulbs, and roots. This vigorous growth requires a steady supply of nutrients to fuel cell development and energy storage.

2. Increased Metabolism: Higher temperatures lead to increased metabolic rates within the plant. Just like humans eat more when they are active, orchids in a high-growth phase need more fuel.

3. More Frequent Watering: As discussed, you'll be watering more frequently in summer. This increased watering can leach nutrients from the potting medium more quickly. Therefore, more frequent fertilization helps replenish these lost nutrients.

Fertilization Strategy for Summer:

• "Weakly, Weekly" Approach: A common and effective strategy for orchids is to fertilize with a diluted solution at every watering, or every other watering. Instead of using full-strength fertilizer once a month, use it at 1/4 to 1/2 strength more frequently. This provides a constant, gentle supply of nutrients without risking fertilizer burn.
• Balanced Fertilizer: Use a balanced orchid fertilizer (e.g., 20-20-20 or 10-10-10) or one formulated for the specific growth phase of your orchid. Some growers prefer a "growth" formula (higher nitrogen) during the active growth period and then switch to a "bloom" formula (higher phosphorus) as flower spikes emerge.
• Flush Regularly: Even with diluted fertilization, salt buildup can occur in the potting medium. To prevent this, once a month, flush the pot thoroughly with plain, clean water for several minutes before fertilizing. This washes away any accumulated mineral salts that could harm the roots.
• Never Fertilize Dry Roots: Always water your orchid thoroughly with plain water first, then apply the diluted fertilizer solution. Applying fertilizer to dry roots can cause severe burn.
• Monitor Your Orchid: Observe your orchid's growth. If new growth looks weak, pale, or stunted despite adequate light and water, it might need more frequent fertilization. If leaves develop brown tips or edges, it could be a sign of over-fertilization (salt burn), indicating you need to flush more frequently or reduce the strength.

By adjusting your fertilization schedule and strength to match your orchid's active growth phase in summer, you provide the necessary nutrients for robust development, setting the stage for abundant future blooms.

When should I consider moving orchids outdoors for summer?

Moving orchids outdoors for summer can be highly beneficial, providing them with enhanced air circulation, natural light, and humidity that are difficult to replicate indoors. However, it's crucial to time this move carefully and choose the right location to ensure their safety and well-being.

When to Move Them Out:

The timing depends on your local climate, but general guidelines are:

1. Consistent Nighttime Temperatures: Wait until nighttime temperatures consistently remain above 55-60°F (13-16°C). Orchids are sensitive to cold, and a sudden drop can shock them.
2. No Frost Risk: Ensure there is zero risk of late spring frosts.
3. Gradual Transition (Hardening Off): Don't move orchids directly from indoors to full outdoor exposure. This sudden change in light, temperature, and humidity can shock them. Instead, gradually acclimate them over a week or two:
   • Start by placing them in a very shady, protected outdoor spot for a few hours a day.
   • Gradually increase their exposure to brighter light and longer periods outdoors over several days.
   • Begin with morning sun and gradually introduce filtered afternoon light.

Where to Place Them Outdoors:

Choosing the right location is paramount:

1. Shade is Key: Most orchids, especially Phalaenopsis, Cattleyas, and Oncidiums, need bright, indirect light. Direct, scorching afternoon sun will lead to sunburn.

   • Ideal Spots: Under the canopy of deciduous trees (they'll provide dappled shade), under a covered patio or porch, or a spot that gets morning sun and afternoon shade.
   • Shade Cloth: If you don't have natural shade, use a horticultural shade cloth (typically 50-70% shade) to create a protective cover.
   • Avoid Solid Surfaces: Don't place pots directly on hot asphalt or concrete, as they radiate heat. Elevate them on benches, hanging baskets, or pot feet.

2. Good Air Circulation: Outdoors, orchids benefit immensely from natural air movement. This helps prevent fungal issues that can arise from increased humidity and frequent watering. Ensure the chosen spot isn't a stagnant, humid pocket.

3. Humidity: Outdoor humidity is generally higher than indoors, which is beneficial for orchids. However, monitor conditions during dry spells.

4. Pest Inspection: Before moving orchids outdoors, inspect them thoroughly for pests. And once outdoors, remain vigilant, as outdoor pests (slugs, snails, insects) can become an issue. Consider using a copper tape barrier for slugs and snails.

5. Wind Protection: While air circulation is good, strong, sustained winds can rapidly dehydrate plants and even knock over pots. Choose a spot that offers some protection from harsh winds.

When to Bring Them Back In:

The reverse process of acclimatization is also important. Bring orchids back indoors when nighttime temperatures consistently drop below 60°F (16°C), well before the first expected frost. Gradually re-acclimate them to indoor light levels.

By carefully planning the move and selecting an appropriate outdoor location, you can provide your orchids with a beneficial summer vacation, promoting vigorous growth and preparing them for a spectacular bloom cycle.

What common pests and diseases should I watch for in summer?

When you grow orchids in summer, the increased warmth and humidity can create ideal conditions for certain pests and diseases to thrive. Vigilant monitoring and prompt action are crucial to prevent widespread problems.

Common Pests to Watch For:

1. Spider Mites: These tiny arachnids love hot, dry conditions. They are often difficult to see with the naked eye, but their damage includes:

   • Symptoms: Fine stippling (tiny yellow or silver dots) on the leaves, usually on the undersides. Severe infestations might show delicate webbing, particularly in leaf axils or on new growth.
   • Location: Often on the undersides of leaves.
   • Treatment: Increase humidity, wipe leaves with a damp cloth, or use insecticidal soap or horticultural oil.

2. Mealybugs: Small, white, cottony-looking insects that feed on plant sap.

   • Symptoms: White, fuzzy masses in leaf axils, on pseudobulbs, or on the undersides of leaves. Leaves may become sticky from honeydew, and sooty mold might develop.
   • Location: Often hidden in crevices, leaf axils, or on new growth.
   • Treatment: Dab individual mealybugs with a cotton swab dipped in rubbing alcohol. For heavier infestations, use insecticidal soap.

3. Scale Insects: Tiny, motionless bumps (brown or clearish) that attach firmly to leaves and stems, sucking sap. They look like raised lesions.

   • Symptoms: Hard, often brown or black, bumps on leaves and stems. Yellowing leaves and honeydew production.
   • Location: Firmly attached to leaves and pseudobulbs.
   • Treatment: Scrape off gently with a fingernail or old toothbrush. Treat with rubbing alcohol or horticultural oil. Repeat treatments are usually necessary.

4. Slugs and Snails (for outdoor orchids): If you move your orchids outdoors, slugs and snails can quickly become a problem, as they feast on new roots, flower spikes, and even leaves.

   • Symptoms: Irregular holes in leaves or roots, slime trails.
   • Treatment: Handpick at night, use slug baits (pet-safe options available), or copper tape around pots.

Common Diseases to Watch For:

Most orchid diseases are fungal or bacterial and are often linked to overwatering, poor air circulation, or water sitting on leaves.

1. Bacterial Soft Rot:

   • Symptoms: Water-soaked, foul-smelling lesions that spread rapidly, often turning black or brown. Can affect leaves or pseudobulbs.
   • Cause: Excess moisture, poor air circulation, high humidity, and warm temperatures.
   • Treatment: Immediate removal of infected plant tissue with a sterile blade. Apply cinnamon (a natural fungicide/bactericide) to cuts. Improve air circulation.

2. Black Rot (Pythium or Phytophthora):

   • Symptoms: Rapidly spreading, dark brown to black soft rot on leaves, pseudobulbs, or roots.
   • Cause: Overwatering, soggy potting medium, poor drainage, and high temperatures.
   • Treatment: Remove infected parts immediately. Repot into fresh, dry medium. Improve drainage and air circulation. Fungicides may be needed for severe cases.

3. Fungal Leaf Spots:

   • Symptoms: Circular or irregular spots (yellow, brown, or black) on leaves.
   • Cause: Water sitting on leaves for too long, high humidity, poor air circulation.
   • Treatment: Improve air circulation, water in the morning, avoid overhead watering. Remove badly affected leaves. Fungicides may be needed.

Prevention is Key:

• Inspect Regularly: Check your orchids weekly for any signs of pests or disease, especially on the undersides of leaves and in leaf axils.
• Good Air Circulation: Essential for preventing fungal issues. Use a fan indoors if needed.
• Proper Watering: Avoid overwatering and ensure excellent drainage.
• Cleanliness: Sterilize tools, remove dead leaves, and keep the growing area clean.
• Quarantine New Plants: Isolate new orchids for several weeks before introducing them to your collection.

By being proactive in monitoring and addressing issues, you can keep your orchids healthy and pest-free throughout the summer months.