How to Check for Nutrient Deficiencies in Plants and Soil

How to Check for Nutrient Deficiencies in Plants and Soil

The last thing us garden-proud, green thumb types want to find when out caring for our gardens, are leaves with yellow spots, stunted growth or curling leaves in plants that should be green and healthy! Obviously, something is wrong but what? And how do you know how to fix it?! A likely cause is nutrient deficiencies in plants and soil.

Nutrient Deficiencies in Plants and Soil

Nutrient deficiencies cause symptoms in our plants that signal nutrient problems. However, it’s not always a simple matter of racing out to buy truckloads of fertilisers and applying them with a vengeance. Other causes could be pests, cold, wind, heat, salinity, water stress… the list goes on.

Another important factor to consider is the role soil pH plays in plant nutrient deficiencies. By determining the measure of acidity or alkalinity, you can figure out what exactly your soil needs to improve it to balance out the pH and save your plants.

Soil pH

The pH scale ranges from 0 -14, with 7 being neutral. Above 7 is alkaline, and below indicates acidic soil. Our Western Australian soils tend to have a pH range of 4 – 8.5, with soils in metropolitan areas being more alkaline as they are nearer the limestone-based coastal sands. Once you head inland or around more agricultural areas, the soil will become more naturally acidic. In home gardens that use mineral fertilisers frequently, the soil pH may have become acidic.

What Does This Mean for My Plants?

In short, soil pH determines the nutrient availability to your garden, as at certain pH levels some nutrients can get ‘stuck’ in the soil and never make it to your plants.

  • Acidic soils can lead to deficiencies in calcium, magnesium, phosphorous, and molybdenum – as well as causing toxic levels of manganese and aluminium.
  • Alkaline soils can result in iron, manganese, copper, boron and zinc deficiencies.

Most plants need neutral soil, pH level 7, to thrive, while some are more suited to a very specific level, so need a more acidic or alkaline soil pH to survive. Check the needs of the plant which is showing symptoms, and either test the soil yourself to see if it is the right pH, or get an landscaping expert in.

Symptoms of Nutrient Deficiency in Plants

1- When symptoms show in the oldest leaves first – as the plant will direct nutrients to the younger shoots to try and stay alive.

Macronutrients:
  • Nitrogen deficiency – premature maternity, leaves yellowing and turning pale green, stunting
  • Phosphorus deficiency – Spindly erect habit, stunted growth, dull blue-green to purple colours in leaves, followed by yellowing
  • Potassium deficiency – leaf margins and tips with yellowing spots, scorched margins, thin short stalks and poor bud formation
  • Magnesium deficiency – patchy yellowing and/or brilliant colouring around the margins of leaves, cupped tips and margins, yellow spots increasing to brown then dying of the leaf
Micronutrients:
  • Molybdenum deficiency – pale mottling over the whole leaf, leaf margin burn, and occasionally stem distortion

2- When symptoms appear in the oldest and youngest leaves – indiscriminately.

  • Manganese deficiency– pale green feathery veins, interveinal yellowing, while some plants can show water-soaked spots that get worse in cloudy weather

3- When symptoms show in the youngest leaves first.

Macronutrients:
  • Calcium deficiency – pale cupped leaves, curling over of the leaf tips, blackening and death of leaves. The other parts of the plant will also start to show damage
  • Sulphur deficiency – paler and smaller leaves that roll down with some pigmentation
Micronutrients:
  • Iron deficiency – Interveinal yellowing, sharply green veins, youngest leaves almost white when the case is severe. This can be common in Perth in areas with alkaline soils/water
  • Copper deficiency – dark blue-green, curling and twisting of leaf tips, distortion and smaller growth than typical
  • Zinc deficiency – small leaves, bunching, shortened distorted stems, or yellow-white interveinal mottling. Can be common in high-pH areas
  • Boron deficiency – shrivelled leaf and shoot tips and crinkled interveinal areas

How to Test Your Soil pH

The best time to test is in Autumn while the soil is relatively dry, has less organic materials and gives you time to adjust levels before the next growing season (Spring).

You can buy soil test kits from most garden centres for a fairly low cost and get a rough reading, or take a soil sample to a soil lab or nursery which offers this service.

  • Don’t mix soil types and use clean containers
  • Take the sample from the top 20cm and try to avoid getting roots and weeds
  • Choose at least 5 spots in the area you wish to test and mix the soils to get an average reading
  • Do not do this after heavy rain, watering or less than 3-4 weeks after fertilising.

Once you have tested your soil and used the reading to determine the root cause of the problem, correcting it is usually a matter of using iron sulphate to increase, or lime to increase the pH.

Acid soils:

To increase the pH by one point, apply dolomite lime at 100 g/m2 for sandy soils, and up to 250 g/m2 for clay. This is a long process and probably won’t show noticeable change for up to 2-3 months.

Alkaline soils:

Decrease the pH by adding iron sulphate – in the amount as shown in the label instructions. This method is almost immediate in comparison to the lime.

Now you have done all this hard work it becomes a matter of maintenance, careful application of the right fertilisers, and monitoring the soil pH.

Check out our blog post for information on choosing the right fertilisers based on your plants, location and soil.

Fixing Nutrient Deficiency of Plants

If identifying nutrient deficiencies in plants and soil in your garden sounds like more hard work than you have time for, give us a call and our expert landscape gardeners will sort you out.

They can test the soil for you, recommend the right fertilisers and maintenance schedule – or just do it all for you! What could be easier?

Have a healthy green garden year-round, contact us to get Perth Gardening on the job!

Guide to Garden Fertilisers

Guide to Garden Fertilisers

Nature does an amazing job of self-nurturing and uses incredibly smart and well-honed systems to keep things green and growing. But our carefully designed home gardens tend to work outside nature with our desire to have them green year-round and use of plants which aren’t native to our location. So sometimes nature needs a little help to provide the nutrients needed to maintain a healthy garden (especially when all leaves and green wastes are removed on a regular basis to maintain a tidy garden)

The Why’s and How’s of Fertilising your garden in Perth.

One of the effective ways to do this is by using the right fertilisers as part of our regular gardening activities.

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So, let’s talk mulch to answer the often asked question “What are the benefits of mulching?”

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Methods of Weed Control

Methods of Weed Control

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Ironically, a lot of our common weeds today were introduced by early settlers in Perth as garden plants! However, they took to our fair country much too well and are now prevalent enough to cause problems that are more than just their appearance. So really, a weed can be defined as any plant growing where it’s not wanted!

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March Gardening Tips

March Gardening Tips

March is the start of Autumn in Perth… and we’re finally starting to feel it! Prepare to be fighting those pesky leaves for the next few months, but also take some time to enjoy those glorious colours of Autumn! We just love how it goes from stunningly royal displays of purple in the Summer to those golden and warm orange tones – always something beautiful to spy around our home here in Perth.

As always, at the beginning of a new season, there is plenty to do, so we have compiled some March gardening tips for you.

Gardening Tips for March

In our March gardening tips we’ll look at what to plant and what needs doing in March. Let’s get started with what needs planting in March.

What to Plant in March

Hand planting in March

This is a great season to be planting all sorts of things and even to begin planning your spring bulbs!

TIP: Before the end of the month you want to have planted your citrus, avocado and olive trees.

What to plant:

HERBS: plant basil, coriander, garlic, garlic chives, mustard, marjoram, oregano, parsley, thyme and winter tarragon.

TIP: Be careful to keep your herbs well-watered and semi-shaded while there are still some hot days this month – they wilt and burn easily!

FRUITS: Plant tomatoes, melons and strawberries.

VEG: Almost everything! Sow beans, beetroot, broccoli, cabbage, capsicum, carrot, cauliflower, celery, Chinese cabbage, cucumber, eggplant, lettuce, mustard, okra, onion, parsnip, potato, pumpkin, radish, rosella, silver beet, squash, sweet corn, sweet potato and zucchini.

FLOWERS: Plant alyssum, lobelia, pansy, stock, sweet pea, snapdragon and viola.

March is ideal for planting trees and shrubs. This month it is getting cooler but the soil is still warm enough to encourage growth in your new greenery – so they have some time to establish their roots before the cold weather sets in!

With that in mind, now is also great for planting new lawns. Summer is the time for outdoor play, and can cause a lot of wear and tear on your grass – often in the form of bare patches in the most used areas, not the best look! By planting now, the new grass seeds will also be able to get their root systems established before the cold, like your trees and shrubs, as well as having months of good growing time before it’s hot again! Make sure you get a qualified lawn expert to help you out if you haven’t done it before, they will be able to make sure it is done right, as well as teach you exactly how to look after it in the following months to ensure it grows lush and green.

Composting and Garden Cleanup in March

Garden Cleanup

You know those lovely leaves that will start to cover every inch of your garden? A great way to get rid of them is to add them to your compost where the worms will love them and you don’t have to see them! You can also add some used coffee grounds to the mix for an extra boost.

March is also a great time for a general garden clean-up to prepare it for the colder months ahead.

  • Trim any branches on your citrus trees that might be hanging lower than 1m – this helps prevent the spread of brown rot.
  • Remove all weeds and any plants in your garden you don’t want to spread – they will all be starting to seed.

We hope that this guide has been helpful and we are sure with the application of these tips and tricks your garden will flourish this month!

Enjoy being out gardening in March in these last warm days – we certainly will!

Have a read through some of our other blogs for some more info on gardening in Perth, or check out some of the gardening services we offer. As it becomes colder your garden still needs lots of TLC, but you might not feel so excited at the thought of getting out in the cold to give it! Contact us and let our friendly and professional landscape gardeners take care of it for you…