Understanding Amaranth Plant Growth Stages: A Comprehensive Guide

Amaranth is an ancient grain that has been cultivated for about 8,000 years. This nutritious gluten-free grain is experiencing a resurgence in popularity as more people discover its health benefits. Amaranth is rich in protein, minerals, and vitamins.

When growing amaranth, it’s helpful to understand the different stages of the plant’s growth cycle. Here is a comprehensive guide to the growth stages of the amaranth plant.

Amaranth Growth Stages

The growth cycle of amaranth can be divided into three main stages

1. Germination Stage

This first stage starts when the amaranth seed begins to sprout. A seed needs moisture, warmth, and oxygen to germinate.

Ideal soil temperature for amaranth seed germination is 70-95°F. Seeds will germinate best when planted 1⁄4 to 1⁄2 inch deep in the soil. Germination usually occurs within 3-8 days.

During germination, the seed coat splits open and a tiny root emerges and grows down into the soil. Next, the shoot emerges and grows upwards. These young seedlings are very vulnerable at this stage. Consistent moisture and protection from direct sunlight is important.

Once the first true leaves appear, the plant has finished the germination phase. This takes around 8-12 days from planting.

2. Vegetative Growth Stage

In this stage, the young amaranth seedling focuses on root and leaf growth. The stem elongates and more leaves emerge. This is sometimes called the “grand growth” phase.

• Leaves: The plant will continuously generate new leaves. Leaves emerge one at a time from the central stem in an alternating pattern. Leaves are green, oval shaped, and smooth.

• Stem: The main stem lengthens rapidly, producing lateral branches with smaller leaves. Amaranth stems are smooth, hairless, and green or red depending on variety.

• Roots: A large taproot forms along with an extensive fibrous root system. This anchors the plant and absorbs water and nutrients.

This vegetative stage lasts 3-6 weeks. The plant becomes bushy and leafy as it soaks up sunlight to power growth. Watering is important during this stage, but avoid overwatering which can lead to fungal diseases.

3. Flowering & Seed Stage

After established vegetative growth, the plant enters the reproductive phase. This transition is triggered by maturity, photoperiod, and temperature.

• Flowers: Small green to white flowers emerge in clusters on terminal spikes at the tops of the main stem and branches. Amaranth is monoecious – each plant has both male and female flowers. Flowers are pollinated by wind.

• Seeds: Fertilized female flowers develop into thousands of tiny lentil-sized seeds clustered in long, drooping seed heads. Seeds start out green and ripen to shades of cream, gold, or black depending on variety.

• Senescence: Once flowering completes and seeds mature, the amaranth plant starts yellowing, withering, and dying back. Plants decline as energy is directed to seeds. Drying seeds are naturally shed over 1-2 weeks.

The time from flowering to harvest can take up to 10 weeks, depending on variety and growing conditions. Total growth cycle length ranges from 4-6 months.

Factors Affecting Growth

Amaranth growth stages are influenced by several key factors:

• Variety – Some amaranth cultivars mature faster than others. Grain types tend to have a shorter life cycle.

• Temperature – Amaranth thrives in warm weather. Optimal growing temperatures are 65-85°F. Cool weather slows growth.

• Photoperiod – Amaranth is a short-day plant, meaning flowering is triggered earlier under short day length. Long summer daylight delays flowering.

• Fertilizer – Applying nitrogen fertilizer boosts leafy growth in vegetative stage. Adequate phosphorus ensures good rooting and seed production.

• Pruning – Removing small lower leaves and lateral shoots encourages larger upper leaves. Pinching stem tips promotes bushiness.

Growth Habits

Amaranth exhibits differing growth habits depending on variety:

• Erect varieties – Tall, upright growth reaching 2-8 feet. Better for grain production.

• Prostrate varieties – Low, spreading growth that can be 1-3 feet tall. Used for leaves.

• Semi-erect varieties – Intermediate habits good for both grain and leaves.

Proper spacing is important to prevent crowding and competition for light. Recommendations range from 4-12 inches between plants and 18-30 inches between rows. Wider spacing is needed for larger erect varieties.

Monitoring Growth Stages

To successfully grow amaranth, it helps to closely monitor developmental stages:

• Observe seedlings daily after planting to ensure good germination rates. Thin overcrowded areas.

• Inspect plants frequently during vegetative stage and provide adequate water and nutrients.

• Watch for first flowers to know when reproductive stage begins.

• Once flowering starts, track seed head development and note when seeds start ripening.

• Check lower leaves for yellowing/drooping as a sign that senescence is approaching.

Keeping detailed notes on dates and observations will help plan future planting timing and determine optimal harvest window.

Growth Stage Timeline

Here is an approximate timeline of the major growth phases:

• Germination – 8-12 days from planting

• Seedling establishment – 4-6 weeks after germination

• Vegetative stage – 4-8 weeks after establishment

• Flowering starts – 8-12 weeks after germination

• Seed setting – 2-4 weeks after first flowers

• Senescence – 1-2 weeks after seeds mature

• Harvest – 13-18 weeks after planting

Timing varies substantially based on cultivar, climate, and other factors. Use general timeframes as a guide, but observe plants closely to determine ideal stage timing.

Harvesting at Different Stages

Amaranth can be harvested at various points in the life cycle:

• Microgreens – Harvest seedlings 2-3 weeks after germination when they reach 2-4 inches tall.

• Leaves – Start harvesting young leaves 3-4 weeks after establishment. Continue picking leaves during vegetative stage.

• Seeds – Allow seeds to fully mature and dry before collecting. Seeds detach easily when rubbed between fingers.

• Entire plants – Uproot entire amaranth plants after seed harvest. Dry and thresh to get all seeds.

Harvest leaves early in the morning and choose young, tender leaves from top and outer parts of plants. Pick seeds when the majority are dry and heads rattle when shaken.