Why does perlite turn green

Start by skimming off the first couple of inches of greenish potting mix on your pot tops, and refresh with new potting mix. It is also important that you have pots that drain well and bottom saucers for watering.

Pots like these will enable bottom watering. Allow the top two inches of potting soil to become dry between watering. This will halt algal growth. Another method is to water your plants from the bottom saucer only when they need it.

To learn more about best-practices for plant watering, read our article How to Water House Plants. You must be logged in to post a comment. If the plants were in obvious distress now, I would transfer them into pots, keep them in pots until they go dormant in December and then plant them somewhere where they get less sun. The reason? I never plant or transplant anything here after mid May.

Hydrangeas begin to suffer from wilting episodes and watering issues as temperatures top 85F and mid-May is about the time when we hit the 90s. Meaning they are dark green and with no signs of browning from the edges inwards.

That browning happens when they do not get enough water for a long enough time. I do not see signs of iron chlorosis the leaves turn light green or yellow with the leaf veins remaining dark green. I see no signs of wilted leaves, although who knows Specially if wilting is making you are water daily The shrub in the middle has some leaves that appear to have some browning.

Could be lack of water or too much sun. It was not clear. I see evidence of soil recently watered in the picture so I thought I would digress and tell you what I do watering wise. The mulch does not have to be acidic as acidic mulch will not help that much. I use hardwood mulch or hay or organic compost in some years. Tried pine needles too but those were a slight pain so I went back to the other stuff.

No rocks as mulch ever. Use either garden sulfur, aluminum sulfate or greensand to acidify the soil. Or use liquid iron-chelated compounds sold at most plant nurseries. The liquids correct iron chlorosis faster than solids but they do not last as long. Then I use either a moisture meter or the finger method to determine if I need to water them. I give mine 1 gallon of water in the Spring per plant per watering and increase that to 1. I go down back to 1 gallon when temperatures moderate in September.

When we hit the daily s or so, I may water using the hose at certain times too. Most of mine have drip irrigation but a few get water from the regular sprinkler. Wilting episodes indicate that the plant is loosing moisture thru the leaves much faster than it can absorb water thru the roots. So blooms and-or leaves wilt. These episodes are common on the first year, when the shrubs have a tiny root system that cut to fit into the 1 or 3 gallon pots.

After mid-May, I check these guys in the mornings. A hydrangea should fix the wilting episode on its own provided that its soil has enough water. If it shows up wilted during my morning inspection then I hand water them. I always water early in the morning and only the soil -never the leaves-. Water from the root ball outwards. The only exception to those suggestions: if I see a wilting episode that seems extreme, I immediately water and maybe check for things like the sprinkler system was not turned on, etc.

In future years, as the plants' root system gets larger and the plants become established, wilting episodes will diminish but happen in very hot, very dry or windy conditions so consider if you want to water the day before the weather service says it will be hot or very windy.

Hard to tell with some Blushing Bride blooms as they are not exactly white. If purchased this year, they may have been forced to bloom early so it may be ok for them to turn brown early. Either due to heat stress or lack of water or lack of enough water. The algae is a sign that you are over watering i believe.

There's most likely a simple solution to it if you look it up here or on google i'm sure someone else has asked. The way the soil is pulled from the side of the pot it looks like it was at some point too dry though. Joined: Mar 11, Messages: Likes Received: Like x 1. Yeah she looks good. No idea why only one pots getting it but pretty certain water is the reason. Like x 2. Joined: Mar 8, Messages: Likes Received: Most likely, a green layer growing on top of your soil is caused by algae.

This green layer is often slimy and slippery at first. Later on, a layer of algae will turn black as it dries out. According to Clemson University, this layer of black algae crust can prevent water from getting into the soil.

Algae is a broad term for an entire group of organisms which share some similarities with plants. The group of algae includes single-celled micro-algae all the way up to giant kelp and seaweeds.

Just like plants, algae use photosynthesis to turn light into energy, and thus they contain chlorophyll. This gives most algae a green color, although there are also brown and red algae.

For more information, check out this article on algae from Wikipedia. Most algae are aquatic, meaning that they live in either freshwater or saltwater.

The algae you see in your garden will thrive in moist and humid environments, such as in a greenhouse or on wet soil. If there is little or no wind or air currents, then the environment will tend to stay moist. This explains why you will see algae more often in a greenhouse or indoors.

Algae have the potential to thrive in anything that holds a lot of water. This includes moisture-absorbing materials that are often found in potting soil, such as:. This explains why you sometimes see the little white balls of perlite in potting mix turn green after over watering your houseplants! The perlite holds onto water, creating a moist environment where the algae can thrive.

Algae grow best in areas with plenty of light. This explains why they tend to do well in greenhouses. Of course, algae are perfectly happy to grow on the surface of your garden soil, as long as it stays wet and gets plenty of sunlight.

The optimal temperature for algae to grow is 68 to 86 degrees Fahrenheit 20 to 30 degrees Celsius. If your greenhouse stays this warm overnight, then you just might be sending algae an invitation to set up a colony. For more information, check out this article from Science Direct on the effect of temperature and light on algae.

For more information, check out this article on algae pH from Algae Research and Supply. Unfortunately, the ideal pH for most plants is 6.

That means that freshwater bacteria will feel right at home on the soil in your garden or greenhouse. Given enough time, moisture, and light, algae can spread over the entire top layer of soil on a tray used to start seedlings.

For more information, check out this article about algae reproduction from Brittanica. Algae are also notorious for growing on the clear plastic walls of some greenhouses. This location helps algae to get plenty of sunlight and grow without competition from other plants.