Sand, Salt and Mould
Answered by: Inge Poot
Question from: Gavin Fish
Posted on: March 18, 2003

I have three questions that need expertise to answer me, and I think you must be the right person:

1. I am living near the ocean and I can gather unlimited amount of sea-sand onto my garden to improve the drainage problem, am I right? But I would like to know will the sea-sand affect the pH of the soil compared with normal sand? And how much sand do I need to add to it in order to balance the drainage issue and keeping the nutrition of the soil?

The problem with sea sand is that it must be washed with sweet (non-salty) water before it is suitable for most garden uses. The sodium in sea-salt kills anything but highly salt tolerant species. This is far more of a problem than the raising of pH it can cause if your soil is on the acid side. In the long run, what the sand is mostly made up of, ie silica or calcareous stone is what will determine its effect on pH. I would suggest that you wash the sand away from your garden so that you don’t destroy your soil with the run-off. You might make a box with a screen bottom, put an old sheet into it, then prop it off the ground and add sand and then hose it down several times. After draining, tip into bed whose drainage needs improving .

How much sand to add will depend very much on what your soil is made up of. At one extreme, heavy clay will need about one third of its volume in sand to break it up, but it will also need an equal amount of compost to give it nutrition and water holding capacity. Living near the sea, might mean that you already have a sandy loam and don’t have to worry about adding any sand.

2. Will the on-shore wind (blowing from the ocean towards my garden) affect the herbs’ growth?

The wind could be bringing a bit of salt with it and mast plants won’t like it. I suggest you either build a wall between you and the prevailing winds (a practice used to great effect by the English) or plant a thick hedge to cut the wind over the herb garden. It will also look charming to enclose the herb garden.

3. I found mould appeared on the surface of the soil under my creeping thyme. The first time I thought it might be too crowded, so i cut the thyme down to ground level to let it have good ventilation. However, the mould grows even better on the cut stems (I think injuries must good for moulds...) and now I can’t control them... I’ve read your answers that powdered sulphur or powdered cinnamon is ideal to kill fungus, so now I would like to know the detailed direction for using them: how much should I add? On the soil or on the leaves? Adding water before or after? How much time do I need to wait if I want to harvest them? ....

Myself, and my thyme are very eager to receive your professional assistance, or the thyme will die soon. :-)

If I understand your problem correctly, the fungus is growing on the soil, not on the plants? Sprinkle any of the three remedies onto the fungus wherever it is located. Scratch the soil slightly under your thyme plants, as that will allow the surface of the soil to dry out better and discourage any fungus. Use a mulch of peat moss under your plants, since it is too acid for most fungi and also contains anti-fungal agents.

Do not water after adding the anti-fungal agents, but rather re-apply a new sprinkling after a rain.

You can also use a strong chamomile tea as an anti-fungal or anti-bacterial spray. Sulphur powder can be suspended in water and applied as a spray, but since fungi love moist conditions, just sprinkling it on may be better. Rubbing alcohol is also a good spray, as is 3-5% hydrogen peroxide solution.

Lastly, just in case your fungus seems to be growing on and out of the plants- it may be a parasitic plant, such as a dodder. If this is the case, burn all affected plants, before the parasite sets seed and infects the next crop!

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