Growing Pea Shoots in a Greenhouse

What Research Actually Supports About Light, CO₂, Tender Growth, Water and Shelf Life Pea shoots and pea microgreens are young seedlings of Pisum sativum harvested long before the plant reaches reproductive maturity. They are often described as easy crops because they: But there is no scientifically established PAR, CO₂ and VPD recipe that guarantees: tender […]

Growing Butterhead Lettuce in a Greenhouse: PPFD, DLI, CO₂ and Tipburn

Butterhead lettuce is valued for: soft leaves, compact heads, tender texture, and high fresh-market quality. But in controlled-environment production, the biggest challenge is not simply producing enough leaf area. It is producing: high biomass without excessive tipburn. Direct research with green butterhead lettuce shows that increasing: PPFD DLI CO₂ or: temperature can accelerate growth. But […]

Growing Mizuna in a Greenhouse: PPFD, DLI, Photoperiod and Quality

Mizuna is a fast-growing Japanese leafy Brassica valued for its: mild peppery flavor, deeply serrated leaves, rapid harvest cycle, and ability to regrow after cutting. It is often treated like a generic leafy green. But direct controlled-environment research shows that mizuna responds strongly to: PPFD Daily Light Integral photoperiod spectrum and: temperature. Most importantly, there […]

Growing Radishes in a Greenhouse: Light, CO₂, Temperature and Root Quality

Radish (Raphanus sativus) is one of the fastest vegetable crops to grow. That short crop cycle can make greenhouse radish look simple. But producing: large uniform crisp and: non-hollow storage roots is more complicated than producing a large canopy. Radish responds strongly to: light quantity light spectrum CO₂ root-zone temperature water availability plant spacing and: […]

Growing Romaine Lettuce in a Greenhouse

Romaine lettuce (Lactuca sativa var. longifolia) is recognizable by its upright growth habit, elongated leaves and prominent midribs. Compared with loose-leaf lettuce, a mature romaine plant can look structurally robust. But that appearance does not mean romaine simply benefits from: more light more CO₂ and: drier air. Direct romaine research shows clear tradeoffs. Increasing Daily […]

Growing Green Onions in a Greenhouse

What Research Actually Supports About Light, CO₂, Regrowth, Water, Texture and Shelf Life Green onions, scallions, Welsh onions and Japanese bunching onions are names commonly used for non-bulbing or weakly bulbing Allium fistulosum crops. They are fast-growing leafy Alliums valued for: Their rapid growth can make them appear almost impossible to stress. But there is […]

Growing Mustard Greens in a Greenhouse

What Research Actually Supports About Light, CO₂, Glucosinolates, Water, Flavor and Shelf Life Mustard greens, commonly Brassica juncea, are fast-growing leafy Brassicas valued for their distinctive peppery flavor. They can be harvested as: But these production stages are not physiologically identical. There is no scientifically established stage-by-stage combination of: PAR CO₂ and: VPD that guarantees: […]

Growing Tarragon in a Greenhouse

What Research Actually Supports About Light, Photoperiod, CO₂, Water Stress and Aroma Tarragon (Artemisia dracunculus L.) is a perennial aromatic herb valued for its narrow leaves and distinctive volatile profile. But “tarragon” is not always one identical crop. For culinary production, French tarragon is especially important. True French tarragon is normally propagated vegetatively because its […]

Growing Chives in a Greenhouse

What Research Actually Supports About Light, CO₂, Regrowth, Water, Temperature and Leaf Quality Chives (Allium schoenoprasum L.) are perennial culinary herbs grown primarily for their hollow green leaves. They tolerate repeated cutting and can remain productive for a long period, which makes them look like a simple greenhouse crop. But chives have a more complicated […]

PAR, CO₂, and VPD Requirements for Greenhouse Swiss Chard at Different Growth Stages

Swiss chard is a productive leafy crop, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every cultivar and every stage of greenhouse production. PAR supplies the photons used for photosynthesis. CO₂ supplies carbon. Temperature and humidity determine the plant-air moisture environment, commonly described using vapor pressure deficit (VPD). These […]

PAR, CO₂, and VPD Requirements for Greenhouse Arugula at Different Growth Stages

Arugula (Eruca sativa), also called salad rocket, is a fast-growing leafy crop that responds strongly to light. But there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse and every growth stage. For arugula, published research gives us particularly useful evidence about: The evidence for one precise arugula-specific VPD optimum […]

PAR, CO₂, and VPD Requirements for Greenhouse Sage at Different Growth Stages

Sage (Salvia officinalis L.) is a Mediterranean aromatic herb that generally performs well under bright conditions, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse and every growth stage. This is especially important for sage because different growers may be optimizing for very different outcomes: The environmental condition […]

PAR, CO₂, and VPD Requirements for Greenhouse Oregano at Different Growth Stages

Oregano is a Mediterranean aromatic herb, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every oregano plant, greenhouse and stage of production. This is especially important because “oregano” can refer to genetically and chemically different plants. Even within Origanum vulgare, different: can produce substantially different essential-oil profiles. One oregano […]

PAR, CO₂, and VPD Requirements for Greenhouse Thyme at Different Growth Stages

Thyme is a Mediterranean perennial herb adapted to bright environments, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse, cultivar and stage of production. This is particularly important for thyme because growers may be optimizing for different outcomes: These outcomes do not always peak under the same environmental […]

PAR, CO₂, and VPD Requirements for Greenhouse Rosemary at Different Growth Stages

Rosemary is a Mediterranean perennial herb that generally performs well under bright conditions, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse and every stage of rosemary growth. This is especially important for rosemary because production goals can differ. A grower may want: Those objectives do not always […]

PAR, CO₂, and VPD Requirements for Greenhouse Dill at Different Growth Stages

Dill is a fast-growing culinary herb, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse, cultivar and stage of production. Light provides the photons used for photosynthesis. CO₂ supplies carbon. Temperature and humidity shape the plant-air moisture environment commonly described using vapor pressure deficit (VPD). For dill, published […]

PAR, CO₂, and VPD Requirements for Greenhouse Parsley at Different Growth Stages

Parsley is a leafy culinary herb, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every cultivar and every stage of greenhouse production. Light supplies the photons used for photosynthesis. CO₂ supplies carbon. Temperature and humidity shape the plant-air moisture environment, commonly described using vapor pressure deficit (VPD). For parsley, […]

Cilantro Light Requirements: PPFD, DLI and Bolting

Cilantro (Coriandrum sativum), also called coriander, is often described as a cool-season herb that prefers good light but bolts quickly when growing conditions become unfavorable. That description is useful. But cilantro lighting is more complicated than: “Give it moderate light and keep PPFD below 700 µmol/m²/s.” Controlled-environment research shows that cilantro responds strongly to: PPFD […]

PAR, CO₂, and VPD Requirements for Greenhouse Peppermint at Different Growth Stages

Peppermint (Mentha × piperita L.) is a fast-growing aromatic herb, but there is no scientifically established PAR, CO₂ and VPD recipe that applies to every greenhouse and every stage of production. This is particularly important for peppermint because plant appearance is only part of the production goal. Growers may be optimizing for: These outcomes do […]

PAR, CO₂, and VPD Requirements for Greenhouse Basil at Different Growth Stages

Sweet basil (Ocimum basilicum) responds strongly to its light environment, temperature, humidity and carbon dioxide supply. However, there is an important limitation when discussing “ideal” PAR, CO₂ or VPD values: There is no single scientifically established PAR, CO₂ and VPD recipe that applies to every basil cultivar, greenhouse and growth stage. Published basil studies use […]

PAR, CO₂, and VPD Requirements for Greenhouse Spinach at Different Growth Stages

Greenhouse spinach is a fast-growing leafy crop, but its performance cannot be explained by light alone. PAR provides the photons used for photosynthesis. CO₂ provides the carbon used to build sugars and biomass. Temperature and humidity determine the plant-air moisture environment, commonly described using vapor pressure deficit (VPD). These variables interact. A spinach canopy may […]

Greenhouse Lettuce: PPFD, DLI, CO₂ and VPD by Growth Stage

Lettuce is often described as an easy controlled-environment crop because its production cycle is relatively short. That does not mean its environmental requirements can be reduced to one light intensity, one CO₂ concentration and one VPD value. A lettuce seedling, a rapidly expanding plant and a nearly market-ready head do not have identical leaf area, […]

Greenhouse Strawberries: CO₂, Temperature, VPD, Flowering and Fruit Quality

Greenhouse strawberries are often managed using a list of environmental targets: a certain light level, a CO₂ concentration, a temperature range and a VPD setpoint. The problem is that strawberries do not respond to these variables independently. CO₂ enrichment can increase photosynthesis and yield, but its benefit depends on temperature and available light. Temperature influences […]

Cucumber Light Requirements: PPFD and DLI from Seedling to Fruiting

Cucumbers are fast-growing, high-light crops once they develop a large canopy and begin producing fruit. But there is no single PPFD number that applies to every cucumber plant from germination through harvest. A young plug seedling and a mature greenhouse cucumber differ dramatically in: For that reason, cucumber lighting is better evaluated using: PPFD — […]

PAR, CO₂, and VPD Requirements for Greenhouse Tomatoes at Different Growth Stages

Greenhouse tomato production is not controlled by light alone. Tomatoes use photosynthetically active radiation (PAR) as the energy source for photosynthesis, CO₂ as the carbon source for building carbohydrates, and the surrounding temperature and humidity determine vapor pressure deficit (VPD), which influences transpiration and stomatal behavior. These factors interact. A tomato canopy may receive strong […]

Why It’s Important to Record CO₂ PPM in Growing Environments

Carbon dioxide is not a fixed background number inside a growing environment. In: greenhouses, grow rooms, vertical farms, and other controlled-environment agriculture systems, CO₂ concentration can change substantially during the day. Plants remove CO₂ from the air when photosynthesis is active. Ventilation brings outside air back into the space. People, combustion sources and intentional CO₂ […]

How PPFD, CO₂ and VPD Interact in Plant Growth

Plant growth is often discussed one variable at a time. How much light does the crop need? What CO₂ concentration is best? What VPD should the greenhouse maintain? Those are useful questions, but plants do not experience light, carbon dioxide and atmospheric moisture independently. They experience them at the same time. Light provides energy for […]