Grow-How: Fertilizer Foundation

by Isabel Vinton

Plants are smart: they can make all the food they need just by sitting around in the sun. But that doesn't mean that a sunny garden plot is all they need to thrive. Each plant needs a complex combination of elements, minerals, bacteria, and fungi to keep them healthy, which is why planting into fertile soil and using additional applications of fertilizer throughout the season is important. Think of fertilizer less like plant food and more like plant vitamins. But with the plethora of types, methods, and timings associated with fertilizer, it can be hard to know how to keep your garden kicking. The best tip we can give you is to follow the instructions on the label. But to help you navigate the wide world of plant nutrition, we've compiled a list of basics.

WHAT'S IN FERTILIZER: Basically all fertilizers contain three main components that all plants need to survive. Nitrogen helps plants produce chlorophyll, which in turn helps them photosynthesize. That means all parts of a plant need nitrogen to grow. Too little can manifest in pale green plants. Phosphorus supports cell division so that roots, stems, blossoms, and fruit can grow big and strong.  Potassium is vital for many chemical processes, including their means of making and digesting food. A potassium deficiency can cause stunted plants and yellow lower leaves. Plants need other trace elements, too, including calcium, magnesium, iron, copper, manganese, zinc, molybdenum, boron, and sulfur. Every plant and every garden plot needs a unique combination of these nutrients. In fact, if you have low-maintenance plants or super fertile soil, you might not need to add much--in fact doing so could overload your plants and cause them harm. One of the best things you can do for your garden is get your soil tested so you can find out exactly what your soil contains and what it might need more of. Contact your local county extension for help with soil testing.

WHEN TO FERTILIZE: The journey to nourished plants starts with the soil they are planted in. An unplanted bed can quickly be hoed and raked multiple times to incorporate a big pile of compost; trying to do a thorough job of this once the seedlings are up is nearly impossible. For that reason, we prefer working compost or fertilizer into soil before planting, and ideally letting the prepped bed sit for 3-7 days before planting. It's much easier to create a fertile bed for your plants before sowing seeds than after they have emerged. Compost and other organic fertilizers can also be mixed into the holes or furrows you're about to plant into. We don't, however, recommend adding much fertilizer to seedling trays. The minerals can build up in their tiny cells in levels too high for them to handle. If it is going to rain, it may be a great time to fertilize, since the rain will help work the nutrients down into the soil. On the other hand, however, big storms or relentless spring rains can wash those amendments right out of your garden, putting all your hard work to waste. It can be a good idea to add a secondary application of fertilizer mid-season, or whenever you think your plants might be getting a bit nutrient starved. As for other fertilizers? The label on the product is your best guide.

HOW MUCH TO FERTILIZE: Every plant has a different nutrient requirement. Some, including brassicas, nightshades, and cucurbits, are known as "heavy feeders" because they take up nutrients at a faster rate and will need them replenished more frequently. Often, these are crops that take a longer time to reach maturity. Others, like greens, beans, and root veggies, are "light feeders" and have less demanding fertilizer needs. At the least, that mid-season reapplication of compost or fertilizer is great for your garden. But how much and how often exactly, you ask? You know what we're about to say: check the label! And keep in mind that too much fertilizer can be just as disastrous as too little.

WHAT TO FERTILIZE WITH: As growers of organic seed, we're strong believers in using organic fertilizer. Why? For one, organic fertilizers are released to the soil slowly. This means the plants have access to them over a longer period of time. Additionally, it helps beneficial microbes flourish, which in turn improves the structure and quality of the soil. Most of the time, organic fertilizers have all the nutrients your plants need. Synthetic fertilizers can and will be taken up by the plants immediately. They can be helpful if your plants need an emergency boost, but they will provide no long-term benefits to plants or soil. Additionally,
Synthetic fertilizers are water-soluble and can leach out into water sources nearby, causing imbalances in the ecosystem.

So what do we recommend? Most store-bought soils are sterile, to assuage gardeners' fears about contaminants that could lead to damping off. If these soils aren't amended, however, the result is unhealthy, nutrient-starved seedlings. To prevent that outcome, be sure to incorporate your compost. Or even better, use a soil that includes compost, like the Lite Mix from McEnroe Organic Farms.

But compost isn't the end of the road for organic fertilizer. There are many other plant-based sources that pack an awesome nutrient punch:

Alfalfa Meal: A great all purpose, natural fertilizer. Alfalfa meal is perfect for roses as well as all other vegetables, herbs, flowers and shrubs. It is derived from sun-cured, non-genetically modified alfalfa that is freshly milled to preserve the highest plant nutrient value.

Vegan Mix: Another all purpose fertilizer made from soybean, canola, and alfalfa meals, rock phosphate, langbeinite, greensand, kelp meal, and humic acids. It's designed to continually nourish your vegetables, herbs and flowers throughout the growing season, and in combination with high-quality compost, it can build soil tilth and improve plant growth, quality and yields.

Kelp Meal: Hand-harvested, carefully dried and milled, this Kelp Meal provides a rich and natural source of Potash and is an ideal nutrient supplement for all types of vegetables, herbs, flowers and perennials.

Humic Acids Mix: The structure of the soil is just as important as the contents. Humic acids retain water, prevent nutrient leaching, and help nutrient uptake for roots and leaves of plants. And they're made from ancient remains of decomposed organic plant materials--how cool is that?!

Root Zone: A reminder of just how complex a plant's relationship is with the soil, Root Zone is a blend of thirty species of beneficial soil organisms that colonize plant roots and expand into the surrounding soil to greatly increase the absorptive surface area of root systems. Mycorrhizal fungi, Trichoderma and a diverse mix of bacterial species work symbiotically to promote improved soil structure and enhanced root growth.

Unlike water and sunlight, soil nutrients aren't visible to us, and thus it's difficult to know how to balance them. Properly fertile soil, however, can make your garden more resistant to pests and disease, and help them survive tough weather conditions. Next time you take your multivitamin, remember your garden might need one too!