My plants are recovering though. The parts that were brown and yellow are turning back into a healthy green colour since i moved them out of the direct sunlight. If it was a problem with the pH then the leaves would remain brown because nothing in the soil was changed when they got the heat stress. And dont seedlings use up the energy stored in the cotyledons first before they absorb nutes from the grow medium? If thats true then the cotyledons on my seedlings are still intact and are feeding the plant. The roots on the plants arn't properly developed yet either, so Im not sure if its a pH problem although it might look like one.
By the way, im just using common sence and research info here so please correct me if im wrong
A
cotyledon (pronounced
/ˌkɒtəlˈiːdən/; "seed leaf" from
Greek: κοτυληδών
kotylēdōn, gen.: κοτυληδόνος
kotylēdonos, from κοτύλη
kotýlē "cup, bowl"), is a significant part of the
embryo within the
seed of a
plant. Upon
germination, the cotyledon may become the embryonic first
leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the
flowering plants (angiosperms). Species with one cotyledon are called
monocotyledonous (or, "monocots") and placed in the class
Liliopsida. Plants with two embryonic leaves are termed
dicotyledonous ("dicots") and placed in the class
Magnoliopsida.
The cotyledons may be ephemeral, lasting only days after emergence, or persistent, enduring a year or more on the plant. The cotyledons contain (or in the case of gymnosperms and monocotyledons, have access to) the stored food reserves of the
seed. As these reserves are used up, the cotyledons may turn green and begin
photosynthesis, or may wither as the first true leaves take over food production for the seedling.
Epigeal versus hypogeal development
Cotyledons may be either
epigeal, expanding on the germination of the seed, throwing off the seed shell, rising above the ground, and perhaps becoming photosynthetic; or
hypogeal, not expanding, remaining below ground and not becoming photosynthetic. The latter is typically the case where the cotyledons act as a storage organ, as in many
nuts and
acorns.
Hypogeal plants have (on average) significantly larger seeds than epigeal ones. They also are capable of surviving if the seedling is clipped off, as
meristem buds remain underground (with epigeal plants, the meristem is clipped off if the seedling is grazed). The tradeoff is whether the plant should produce a large number of small seeds, or a smaller number of seeds which are more likely to survive.[SUP]
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You have chlorosis on both sets bud.. You say you dont but your pics say different ;P. And as i said if your PH isnt right its going to lock out nutrients.
Plants need several things to make their own food.
They need:
- chlorophyll, a green pigment found in the leaves of plants (see the layer of chlorophyll in the cross-section of a leaf below)
- light (either natural sunlight or artificial light, like from a light bulb)
- carbon dioxide (CO[SUB]2[/SUB])(a gas found in the air; one of the gases people and animals breathe out when they exhale)
- water (which the plant collects through its roots)
- nutrients and minerals (which the plant collects from the soil through its roots)
Plants make food in their leaves. The leaves contain a pigment called chlorophyll, which colors the leaves green. Chlorophyll can make food the plant can use from carbon dioxide, water, nutrients, and energy from sunlight. This process is called photosynthesis.
During the process of photosynthesis, plants release oxygen into the air. People and animals need oxygen to breathe.
How will the plant keep getting food from the leaves if it gets nutrient lock and cant anymore? Yeah theres some food stored now but how about 1 month from now? You cant go thinking like that man.. And even worse if there is nute lock and you keep giving it nutes you gonna get salt build up and theres another issue on its own bud.... Use our common sense for now not yours plz
(dont be offended by that please lol)