addition to my question from a while ago about humidity ( 70 plants ). Id like do add more information because i cant add answear do my post that why i add

RELATIVE HUMIDITY The term ‘relative humidity’ (RH) refers to the amount of water vapor in the air and is usually expressed as a percentage (e.g. 50% RH). This can have a major impact on how cannabis plants grow. Low humidity means less water in the air and results in increased evaporation and water use. Excessive humidity comes with its own problems, including creating an ideal environment for pests, mildew, and mold to grow. One key factor related to humidity that is often left out of the conversation is vapor-pressure deficit (VPD) – the difference between the maximum water vapor the air can hold at a given temperature and RH. Although not all growers measure VPD, it significantly influences stomata activity and is directly related with transpiration rate and metabolism. A VPD that is too high means drier air and increased evaporation and transpiration. Too low a VPD can lead to slowed transpiration and reduced growth. Since slowed transpiration reduces nutrient uptake, both too high and too low of a VPD may appear as nutrient deficiencies. It is VPD that drives transpiration and nutrient uptake in plants; the uptake of water at the roots is determined by the loss of water through the shoots, and the loss of water through the shoots is determined by how much water is in the air. Humidity levels influence the rate of water evaporation from the leaves of cannabis plants, which directly affects the tension and suction created within the plant. Higher humidity levels can reduce the rate of evaporation, potentially impacting the negative pressure and water transport efficiency within the plant. CARBON-e DIOXIDE Carbon dioxide is essential for photosynthesis. Light energy is used to convert CO2 and H2O into sugar and oxygen. As the CO2 concentration increases, the rate of photosynthesis increases until a saturation point where no more CO2 can be absorbed. The guard cells (stomata) previously mentioned are specialized to regulate gas exchange, working to optimize the movement of oxygen, water, and CO2 in and out of the shoots. Plants cultivated outside typically don’t need supplemental CO2 (because nature knows what it’s doing). Indoor growers however, may find themselves needing additional carbon dioxide to maximize yields and improve plant growth and development. Without fresh air for plants to exchange oxygen for carbon dioxide, the CO2 concentrations can become low, hindering photosynthesis and dramatically reducing plant growth. Although CO2 is a naturally occurring gas that both humans and plants use, it is invisible and odorless and can be fatal at high-levels. If you’re supplementing carbon dioxide in your grow room, ensure there are no leaks in any CO2 devices and always use a CO2 monitor and alarm. 0.02% Life unsustainable 0.03% Life OK 0.04% Current ambient atmospheric co2 1.12% CurrentGrow is at 1124ppm co2 this would be 1.12% AIRFLOW Outdoor plants are constantly exposed to natural elements, and that includes wind. Airflow ventilation is one of the often-forgotten environmental factors in healthy cannabis growth and development. Like all environmental factors, we want to “recreate” beneficial stressors that the plant would be exposed to outdoors. Like human bone that becomes stronger in response to stress from resistance we call exercise, stems increase in rigidity and structural integrity in response to stress from air flow. Plants that lack airflow are prone to developing weak stems, leaving them tall, skinny, and unable to hold bud weight as the plant grows. Excessive air flow, on the other hand, which constantly bends the entire plant, could lead to stunted growth or even broken shoots. Thankfully, you don’t need a wind sensor to achieve optimal air flow; a light breeze that just makes the leaves wave or dance gently can assist in the development of strong, dense shoots. A little too much though can stress so be careful not to overdo it too hard for too long as it will eventually stress. Stagnant air within the grow space can also increase the risk of pests, mold, and mildew. Some pests hide under leaves, along stems, and even in the soil itself. A small fan providing a gentle breeze is often enough to prevent a stationary environment, build stem strength, and reduce the chance of pests or pathogens. Proper air circulation and CO2 exchange facilitated by negative pressure contribute to stronger and healthier plants. Good air flow with constant fresh air is essential for maximizing the growth and yield of your indoor plants.. To achieve and maintain negative pressure in your grow tent, several key factors and components come into play. Understanding how these elements work together is essential for creating negative pressure inside your grow tent.Start by selecting an exhaust fan with an appropriate CFM (cubic feet per minute) rating for your specific grow tent size. The CFM rating determines the amount of air the fan can move per minute, and it’s crucial to choose a fan that can sufficiently exchange the air within the tent to create negative pressure. Install the exhaust fan at the highest point in the grow tent to effectively remove warm and stale air from the space. Mounting the fan near the top allows it to expel the warm air, which naturally rises.The negative pressure then automatically draws in fresh air from the lower intake points. Depending on the size and airflow requirements of your grow tent, consider adding a lower intake fan to facilitate controlled air exchange. An intake fan can help regulate the inflow of fresh air and contribute to maintaining balanced pressure within the tent. Want the exhaust higher CFM than lower Intakes, this is what will give us a negative pressure The passive air intake point in the lower portion of the tent allows fresh air to enter passively. Properly positioned and sized passive intake openings ensure a steady flow of fresh air, contributing to the creation of negative pressure when combined with the exhaust fan’s airflow. Co2's density is such gravity pulls it to the bottom 2-3 inches of any enclosure. Adjust passive intake accordingly, as close to the floor as possible. Currently have a 4" intake injecting co2 rich air into/through rootzone as my passive, this pours CO2 dense air around plants 360 degrees from a central point, when the main exhaust kicks in and negative pressure goes into HIGH mode pulling air through rootzones/medium-full temperature, oxygenation of rootzones, wicking moisture. Full HVAC control. Slight negative pressure is good for maximizing the yield of a growth regime. It makes it easier to control the temperature, humidity, CO2 levels, and other contaminants of the tent. Well, too much of everything is always bad. And the same does for negative pressure as well. So, how would you understand whether the negative pressure exceeded the limit? The simple trick is- if the tent itself seems to pull itself inwards, the negative pressure is still under the tolerable limit. If the pressure gets as high as it bends the poles inwards, that’s where the danger limit starts. So, if you see the poles bend inwards, the negative pressure is something to worry about. Otherwise, if it’s the tent itself if pulled inwards slightly, you don’t have to worry about it. The cohesion-tension theory explains how negative pressure enables water movement from the roots to the leaves of a cannabis plant. As water evaporates from the leaf surfaces through stomata, tension is created, generating a suction force that pulls water upwards through the xylem vessels. This process relies on the cohesive forces between water molecules, forming a continuous column for efficient water transport. In cannabis plants, xylem vessels serve as the conduits for water transport. These specialized cells form interconnected channels that allow water to move upwards from the roots to the leaves. The negative pressure generated through the cohesion-tension mechanism helps drive the water flow within the xylem vessels. Negative pressure facilitates the movement of water from the soil, through the roots, and up to the leaves of cannabis plants. It helps maintain proper hydration and turgor pressure, ensuring the cells remain firm and upright. This is crucial for healthy growth and structural support. Negative pressure transports water and aids in the uptake and transport of dissolved nutrients within the cannabis plant. As water is pulled up through the xylem vessels, essential nutrients and minerals are transported along with it, supplying the various tissues and organs where they are needed for optimal growth and development. ROOTS OXYGEN As well as releasing oxygen created during photosynthesis, plants need to absorb oxygen to perform respiration – i.e. to make energy. Since plant roots are non-photosynthetic tissues that can’t produce oxygen, they get it from air pockets in the soil or grow medium. These air pockets can vary in size based on the makeup of the growing medium, and also on the water saturation levels of the medium. Root oxygenation and soil aeration play an important role in both transpiration and cellular respiration in all plants. This means that plants are highly dependent on the growing medium that holds the optimal amount of oxygen within. Make sure not to overwater, as roots in compacted soil or fully submerged in water with low O2 can cause irreversible damage if left unchecked. This is why even when growing hydroponically, when the roots are submerged in water, it’s important to have an air pump to incorporate adequate O2 to the roots. Grow mediums like coco coir and soils that contain perlite promote aeration and are less prone to overwatering. TEMPS Whether it’s sunlight outdoors or artificial lights indoors, when light heats the air temperature, soil temperature also rises. But it’s not only the air that influences the soil temperature; the grow medium, plant depth, and moisture level can also change how well the soil releases or retains heat. Not all growers monitor soil temperature, but roots are the reservoir system of water and nutrients, and if they are the wrong temperature, things can deteriorate quickly for any plant. Roots are a living part of the plant and therefore have an optimal temperature range in which they thrive at water and nutrient uptake. Although every plant varies, root temperatures above 88°F & below 55°F (above 31°C and below 12°C) can result in stunted growth and ultimately plant death if exposed for too long. 73-76, Avoid going over 77F as common bacterial growth explodes above 77, if disease strikes it's going to strike 10x faster above 77F. WATER Water is one of the most important factors of cannabis growth and development; both transpiration and photosynthesis involve water. Irregular watering can lead to irregular plant growth and development. Too little water and your plant can become dry, brittle, and stressed. Too much water and your plant’s roots can be deprived of important oxygen, and even drown. One of water’s most important purposes is the transportation and movement of nutrients and minerals, which are typically absorbed in the roots and distributed throughout the rest of the plant. The faster the plant can rid itself of water through transpiration the faster it can uptake more water to get more nutrients to where they need to be, by creating a negative pressure we optimize turgor pressure increasing nutrient uptake, by sticking to VPD we optimize transpiration rate and maximize stomatal openings, with sound frequency we open them further.